U.S. patent application number 12/070784 was filed with the patent office on 2008-08-28 for compositions containing chromium, oxygen, and at least two modifier metals selected the group consisting of gold, silver, and palladium, their preparation, and their use as catalysts and catalyst precursors.
Invention is credited to Velliyur Nott Mallikarjuna Rao, Allen Capron Sievert.
Application Number | 20080207962 12/070784 |
Document ID | / |
Family ID | 39716677 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080207962 |
Kind Code |
A1 |
Rao; Velliyur Nott Mallikarjuna ;
et al. |
August 28, 2008 |
Compositions containing chromium, oxygen, and at least two modifier
metals selected the group consisting of gold, silver, and
palladium, their preparation, and their use as catalysts and
catalyst precursors
Abstract
A catalyst composition is disclosed that includes chromium,
oxygen, and at least two of gold, silver, and palladium as
essential constituent elements. The amount of modifier metals
(gold, silver, and/or palladium) in the composition is from about
0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals. Also disclosed is a process for
changing the fluorine distribution (i.e., content and/or
arrangement) in a hydrocarbon or halogenated hydrocarbon in the
presence of the catalyst composition; and methods for preparing
said catalyst composition. One preparation method involves (a)
co-precipitating a solid by adding ammonium hydroxide (aqueous
ammonia) to an aqueous solution of soluble salts of modifier metals
and a soluble chromium salt that contains at least three moles of
nitrate per mole of chromium in the solution and has a modifier
metal content of from about 0.05 atom % to about 10 atom % of the
total content of modifier metals and chromium in the solution to
form an aqueous mixture containing co-precipitated solid; (b)
drying the co-precipitated solid formed in (a); and (c) calcining
the dried solid formed in (b) in an atmosphere containing at least
10% oxygen by volume. Another preparation method involves (a)
impregnating solid chromium oxide with a solution of a soluble
modifier metal salts; (b) drying the impregnated chromium oxide
prepared in (a); and optionally; (c) calcining the dried solid. Yet
another preparation method involves mixing multiple compositions,
each comprising chromium, oxygen, and at least one modifier
metal.
Inventors: |
Rao; Velliyur Nott
Mallikarjuna; (Wilmington, DE) ; Sievert; Allen
Capron; (Elkton, MD) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1122B, 4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
39716677 |
Appl. No.: |
12/070784 |
Filed: |
February 21, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60903218 |
Feb 23, 2007 |
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60927846 |
May 4, 2007 |
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60927848 |
May 4, 2007 |
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60927838 |
May 4, 2007 |
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60927847 |
May 4, 2007 |
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60927839 |
May 4, 2007 |
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60927843 |
May 4, 2007 |
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60927842 |
May 4, 2007 |
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Current U.S.
Class: |
570/156 ;
502/228; 502/313; 502/317; 570/123; 570/169 |
Current CPC
Class: |
B01J 37/26 20130101;
C07C 17/25 20130101; B01J 23/685 20130101; C07C 19/08 20130101;
C07C 17/206 20130101; B01J 37/03 20130101; C07C 17/21 20130101;
C07C 17/04 20130101; C07C 17/23 20130101; C07C 17/206 20130101;
C07C 17/23 20130101; C07C 17/25 20130101; C07C 21/18 20130101; B01J
37/14 20130101; C07C 21/18 20130101; C07C 19/08 20130101; C07C
19/10 20130101; C07C 21/18 20130101; C07C 19/08 20130101; B01J
23/6522 20130101; C07C 17/04 20130101; C07C 19/10 20130101; C07C
17/21 20130101; B01J 37/0201 20130101; C07C 17/21 20130101 |
Class at
Publication: |
570/156 ;
502/313; 502/317; 502/228; 570/123; 570/169 |
International
Class: |
C07C 17/23 20060101
C07C017/23; B01J 23/26 20060101 B01J023/26 |
Claims
1. A catalyst composition, comprising chromium, oxygen, and at
least two modifier metals selected from the group consisting of
gold, silver, and palladium, as essential constituent elements
thereof, wherein the total amount of modifier metals is from about
0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition.
2. The catalyst composition of claim 1 further comprising fluorine
as an essential constituent element.
3. The catalyst composition of claim 1 comprising gold and silver
in a mole ratio of from about 10:1 to about 1:10.
4. The catalyst composition of claim 1 comprising gold and
palladium in a mole ratio of from about 10:1 to about 1:10.
5. The catalyst composition of claim 1 comprising silver and
palladium in a mole ratio of from about 10:1 to about 1:10.
6. The catalyst composition of claim 1, comprising particles of
modifier metals supported on a chromium oxide support.
7. A process for changing the fluorine distribution in a
hydrocarbon or halogenated hydrocarbon in the presence of a
catalyst, characterized by using the catalyst composition of claim
1 as the catalyst.
8. The process of claim 7 wherein the fluorine content of a
halogenated hydrocarbon compound or an unsaturated hydrocarbon
compound is increased by reacting said compound with hydrogen
fluoride in the vapor phase in the presence of said catalyst
composition.
9. The process of claim 7 wherein the fluorine content of a
halogenated hydrocarbon compound or a hydrocarbon compound is
increased by reacting said compound with HF and Cl.sub.2 in the
presence of said catalyst composition.
10. The process of claim 7 wherein the fluorine distribution in a
halogenated hydrocarbon compound is changed by isomerizing said
halogenated hydrocarbon compound in the presence of said catalyst
composition.
11. The process of claim 7 wherein the fluorine distribution in a
halogenated hydrocarbon compound is changed by disproportionating
said halogenated hydrocarbon compound in the presence of said
catalyst composition.
12. The process of claim 7 wherein the fluorine content of a
halogenated hydrocarbon compound is decreased by
dehydrofluorinating said halogenated hydrocarbon compound in the
presence of said catalyst composition.
13. The process of claim 7 wherein the fluorine content of a
halogenated hydrocarbon compound is decreased by reacting said
halogenated hydrocarbon compound with HCl in the vapor phase the
presence of said catalyst composition.
14. A method for preparing the catalyst composition of claim 1,
comprising: (a) co-precipitating a solid by adding ammonium
hydroxide to an aqueous solution of a soluble modifier metal salts
and a soluble chromium salt that contains at least three moles of
nitrate per mole of chromium in the solution and has a modifier
metal content of from about 0.05 atom % to about 10 atom % of the
total content of modifier metal and chromium in the solution, to
form an aqueous mixture containing co-precipitated solid; (b)
drying said co-precipitated solid formed in (a); and (c) calcining
said dried solid formed in (b) in an atmosphere containing at least
10% oxygen by volume.
15. The method of claim 14 further comprising treating a calcined
solid formed in (c) with a fluorinating agent to form a catalyst
composition comprising chromium, oxygen, modifier metals, and
fluorine as essential elements.
16. A method for preparing the catalyst composition of claim 1,
comprising: (a) impregnating solid chromium oxide with a solution
of a soluble modifier metal salts; (b) drying the impregnated
chromium oxide prepared in (a); and (c) calcining the dried
solid.
17. The method of claim 16 further comprising treating a calcined
solid formed in (c) with a fluorinating agent to form a catalyst
composition comprising chromium, oxygen, modifier metals, and
fluorine as essential elements.
18. A method for preparing the catalyst composition of claim 1,
comprising: mixing multiple compositions, each comprising chromium,
oxygen, and at least one modifier metal.
19. The method of claim 18 further comprising treating the mixture
of multiple compositions with a fluorinating agent to form a
catalyst composition comprising chromium, oxygen, modifier metals,
and fluorine as essential elements.
20. A process for making CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CHFCH.sub.2F, comprising: (a) reacting HF, Cl.sub.2, and at
least one halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein
each X is independently selected from the group consisting of F and
Cl, to produce a product comprising CF.sub.3CCl.sub.2CClF.sub.2 and
CF.sub.3CClFCCl.sub.2F, wherein said CF.sub.3CCl.sub.2CClF.sub.2
and CF.sub.3CClFCCl.sub.2F are produced in the presence of a
catalyst composition of claim 1; (b) reacting
CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F produced in
(a) with H.sub.2, to produce a product comprising
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F; and (c)
recovering CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F from
the product produced in (b).
21. A process for the manufacture of at least one compound selected
from the group consisting of 1,3,3,3-tetrafluoropropene and
2,3,3,3-tetrafluoropropene, comprising: (a) reacting hydrogen
fluoride, chlorine, and at least one halopropene of the formula
CX.sub.3CCl.dbd.CClX, wherein each X is independently selected from
the group consisting of F and Cl, to produce a product comprising
CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F, wherein
said CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F are
produced in the presence of a catalyst composition of claim 1; (b)
reacting CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F
produced in (a) with hydrogen to produce a product comprising
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F; (c)
dehydrofluorinating CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CHFCH.sub.2F produced in (b) to produce a product
comprising CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2; and (d)
recovering at least one compound selected from the group consisting
of CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2 from the product
produced in (c).
22. A process for the manufacture of 1,1,1,3,3,3-hexafluoropropane
and at least one compound selected from the group consisting of
1,1,1,2,3,3-hexafluoropropane and hexafluoropropene, comprising:
(a) reacting HF, Cl.sub.2, and at least one halopropene of the
formula CX.sub.3CCl.dbd.CClX, wherein each X is independently
selected from the group consisting of F and Cl, to produce a
product comprising CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2, wherein said CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 are produced in the presence of a catalyst
composition of claim 1; (b) reacting CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 produced in (a) with hydrogen, optionally in
the presence of HF, to produce a product comprising
CF.sub.3CH.sub.2CF.sub.3 and at least one compound selected from
the group consisting of CHF.sub.2CHFCF.sub.3,
CF.sub.3CF.dbd.CF.sub.2 and CF.sub.3CFHCF.sub.3; and (c) recovering
from the product produced in (b), CF.sub.3CH.sub.2CF.sub.3 and at
least one compound selected from the group consisting of
CHF.sub.2CHFCF.sub.3, CF.sub.3CF.dbd.CF.sub.2 and
CF.sub.3CFHCF.sub.3.
23. A process for the manufacture of at least one compound selected
from the group consisting of 1,1,3,3,3-pentafluoropropene and
1,2,3,3,3-pentafluoropropene, comprising: (a) reacting hydrogen
fluoride, chlorine, and at least one halopropene of the formula
CX.sub.3CCl.dbd.CClX, wherein each X is independently selected from
the group consisting of F and Cl, to produce a product comprising
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2, wherein said
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2 are produced
in the presence of a catalyst composition of claim 1; (b) reacting
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2 produced in
(a) with hydrogen, optionally in the presence of hydrogen fluoride,
to produce a product comprising CF.sub.3CH.sub.2CF.sub.3 and
CF.sub.3CHFCHF.sub.2; (c) dehydrofluorinating
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 produced in (b)
to produce a product comprising CF.sub.3CH.dbd.CF.sub.2 and
CF.sub.3CF.dbd.CHF; and (d) recovering at least one compound
selected from the group consisting of CF.sub.3CH.dbd.CF.sub.2 and
CF.sub.3CF.dbd.CHF from the product produced in (c).
24. A process for making at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3, comprising:
(a) reacting HF, and at least one halopropene of the formula
CX.sub.3CCl.dbd.CClX, wherein each X is independently selected from
the group consisting of F and Cl, to produce a product comprising
at least one compound selected from CF.sub.3CCl.dbd.CF.sub.2 and
CF.sub.3CHClCF.sub.3, wherein said CF.sub.3CCl.dbd.CF.sub.2 and
CF.sub.3CHClCF.sub.3 are produced in the presence of a catalyst
composition of claim 1; (b) reacting at least one compound selected
from CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 produced in
(a) with H.sub.2, optionally in the presence of HF, to produce a
product comprising at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3; and (c)
recovering at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 from the
product produced in (b).
25. A process for the manufacture of at least one compound selected
from the group consisting of 1,3,3,3-tetrafluoropropene and
1,1,3,3,3-pentafluoropropene, comprising: (a) reacting HF, and at
least one halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein
each X is independently selected from the group consisting of F and
Cl, to produce a product comprising at least compound selected from
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3, wherein said
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 are produced in
the presence of a catalyst composition of claim 1; (b) reacting at
least compound selected from CF.sub.3CCl.dbd.CF.sub.2 and
CF.sub.3CHClCF.sub.3 produced in (a) with H.sub.2, optionally in
the presence of HF, to produce a product comprising at least
compound selected from CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CH.sub.2CF.sub.3; and (c) dehydrofluorinating at least
compound selected from CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CH.sub.2CF.sub.3 produced in (b) to produce a product
comprising at least compound selected from CF.sub.3CH.dbd.CHF and
CF.sub.3CH.dbd.CF.sub.2; and (d) recovering at least one compound
selected from the group consisting of CF.sub.3CH.dbd.CHF and
CF.sub.3CH.dbd.CF.sub.2 from the product produced in (c).
Description
[0001] This application claims priority of U.S. Patent Application
60/903,218 filed Feb. 23, 2007, and U.S. Patent Applications
60/927,846, 60/927,848, 60/927,838, 60/927,847, 60/927,839,
60/927,843, 60/927,842 filed May 4, 2007.
FIELD OF THE INVENTION
[0002] The present invention relates to catalyst compositions
containing chromium, oxygen, and at least two of gold, silver, and
palladium. The present invention also relates to the preparation of
these catalyst compositions, and their use for the catalytic
processing of hydrocarbons and/or halogenated hydrocarbons.
BACKGROUND OF THE INVENTION
[0003] A number of chlorine-containing halocarbons are considered
to be detrimental toward the Earth's ozone layer. There is a
worldwide effort to develop materials having lower ozone depletion
potential and/or lower global warming potential that can serve as
effective replacements for these halocarbons. Thus, there is a need
for manufacturing processes that provide halogenated hydrocarbons
that have lower ozone depletion potential and/or lower global
warming potential (e.g., materials that contain less chlorine or no
chlorine such as saturated and unsaturated hydrofluorocarbons). The
production of hydrofluorocarbons (i.e., compounds containing only
carbon, hydrogen and fluorine), has been the subject of
considerable interest to provide environmentally desirable products
for use as solvents, foam expansion agents, refrigerants, cleaning
agents, aerosol propellants, heat transfer media, dielectrics, fire
extinguishants and power cycle working fluids. For example,
1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene,
1,1,3,3,3-pentafluoropropene and 1,2,3,3,3-pentafluoropropene have
utility in such applications; 1,1,1,3,3-pentafluoropropane has
utility as a blowing agent, and 1,1,1,2,3-pentafluoropropane has
utility as a refrigerant; 1,1,1,3,3,3-hexafluoropropane and
1,1,1,2,3,3,3-heptafluoropropane have utility as fire
extinguishants and 1,1,1,2,3,3-hexafluoropropane has utility as a
refrigerant. In addition, these materials can also serve as
starting materials and/or intermediates for the production of other
fluorinated molecules. Hexafluoropropene is a useful monomer for
preparation of fluoropolymers.
[0004] Certain metal oxides are used as catalysts and/or catalyst
precursors in the manufacture of fluorinated hydrocarbons. Chromium
oxide in particular is useful as it has been found that it may be
fluorinated by HF at elevated temperature to a give mixture of
chromium fluoride and chromium oxyfluoride species which are active
catalysts for conversion of C--Cl bonds to C--F bonds in the
presence of HF. This conversion of C--Cl bonds to C--F bonds by the
action of HF, known generally as halogen exchange, is a key step in
many fluorocarbon manufacturing processes.
[0005] Chromium oxide compositions useful as catalyst precursors
may be prepared in various ways or may take various forms. Chromium
oxide suitable for vapor phase fluorination reactions may be
prepared by reduction of Cr(VI)trioxide, by dehydration of
Guignet's green, or by precipitation of Cr(III) salts with bases
(see U.S. Pat. No. 3,258,500). Another useful form of chromium
oxide is hexagonal chromium oxide hydroxide with low alkali metal
ion content as disclosed in U.S. Pat. No. 3,978,145. Compounds such
as MF.sub.4 (M=Ti, Th, Ce), MF.sub.3 (M=Al, Fe, Y), and MF.sub.2
(M=Ca, Mg, Sr, Ba, Zn) have been added to hexagonal chromium oxide
hydroxide to increase catalyst life as disclosed in U.S. Pat. No.
3,992,325.
[0006] A form of chromium oxide that is a precursor to a
particularly active fluorination catalyst is that prepared by
pyrolysis of ammonium dichromate as disclosed in U.S. Pat. No.
5,036,036.
[0007] The addition of other compounds (e.g., other metal salts) to
supported and/or unsupported chromium-based fluorination catalysts
has been disclosed. Australian Patent Document No. AU-A-80340/94
discloses bulk or supported catalysts based on chromium oxide (or
oxides of chromium) and at least one other catalytically active
metal (e.g., Mg, V, Mn, Fe, Co, Ni, or Zn), in which the major part
of the oxide(s) is in the crystalline state (and when the catalyst
is a bulk catalyst, its specific surface, after activation with HF,
is at least 8 m.sup.2/g). The crystalline phases disclosed include
Cr.sub.2O.sub.3, CrO.sub.2, NiCrO.sub.3, NiCrO.sub.4,
NiCr.sub.2O.sub.4, MgCrO.sub.4, ZnCr.sub.2O.sub.4 and mixtures of
these oxides. U.S. Patent Application Publication No.
US2001/0011061 A1 discloses chromia-based fluorination catalysts
(optionally containing Mg, Zn, Co, and Ni) in which the chromia is
at least partially crystalline.
[0008] Other compositions and preparation methods are disclosed in
U.S. Pat. No. 5,494,873, U.S. Patent Application Publication No.
US2005/0228202, U.S. Patent Application Publication No.
US2005/0227865, and U.S. Patent Application Publication No.
US2007/0004585.
[0009] There remains a need for catalysts that can be used for
processes such as the selective fluorination and chlorofluorination
of saturated and unsaturated hydrocarbons, hydrochlorocarbons,
hydrochlorofluorocarbons, and chlorofluorocarbons, the fluorination
of unsaturated fluorocarbons, the isomerization and
disproportionation of fluorinated organic compounds, the
dehydrofluorination of hydrofluorocarbons, and the
chlorodefluorination of fluorocarbons.
SUMMARY OF THE INVENTION
[0010] This application includes seven different general categories
of invention designated below by sections A through G,
respectively.
A.
[0011] This invention provides a catalyst composition comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements thereof, wherein the total amount of modifier
metals is from about 0.05 atom % to about 10 atom % based on the
total amount of chromium and modifier metals in the catalyst
composition.
[0012] This invention also provides a process for changing the
fluorine distribution (i.e., content and/or arrangement) in a
hydrocarbon or halogenated hydrocarbon in the presence of a
catalyst. The process is characterized by using said catalyst
composition of this invention as the catalyst.
[0013] This invention also provides a method for preparing said
catalyst composition. The method comprises; (a) co-precipitating a
solid by adding ammonium hydroxide (aqueous ammonia) to an aqueous
solution of soluble modifier metal salts and a soluble chromium
salt that contains at least three moles of nitrate (i.e.,
NO.sub.3.sup.-) per mole of chromium (i.e., Cr.sup.+3) in the
solution and has a modifier metal content of from about 0.05 atom %
to about 10 atom % of the total content of modifier metals and
chromium in the solution to form an aqueous mixture containing
co-precipitated solid; (b) drying said co-precipitated solid formed
in (a); and (c) calcining said dried solid formed in (b) in an
atmosphere containing at least 10% oxygen by volume.
[0014] This invention further provides another method for preparing
said catalyst composition. The method comprises (a) impregnating
solid chromium oxide with a solution of a soluble modifier metal
salts, (b) drying the impregnated chromium oxide prepared in (a);
and optionally, (c) calcining the dried solid.
[0015] This invention further provides yet another method for
preparing said catalyst composition. The method comprises mixing
multiple compositions, each comprising chromium, oxygen, and at
least one modifier metal.
B.
[0016] This invention provides a process for making
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and CF.sub.3CHFCH.sub.2F
(HFC-245eb). The process comprises (a) reacting hydrogen fluoride
(HF), chlorine (Cl.sub.2), and at least one halopropene of the
formula CX.sub.3CCl.dbd.CClX, wherein each X is independently
selected from the group consisting of F and Cl, to produce a
product comprising CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and
CF.sub.3CClFCCl.sub.2F (CFC-215bb), wherein said
CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F are produced
in the presence of a catalyst composition comprising chromium,
oxygen, and at least two modifier metals selected from the group
consisting of gold, silver, and palladium as essential constituent
elements, wherein the total amount of modifier metals in said
catalyst composition is from about 0.05 atom % to about 10 atom %
based on the total amount of chromium and modifier metals in the
catalyst composition; (b) reacting CF.sub.3CCl.sub.2CClF.sub.2 and
CF.sub.3CClFCCl.sub.2F produced in (a) with hydrogen (H.sub.2), to
produce a product comprising CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa)
and CF.sub.3CHFCH.sub.2F (HFC-245eb); and (c) recovering
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F from the product
produced in (b).
C.
[0017] This invention provides a process for making at least one
compound selected from the group consisting of
1,3,3,3-tetrafluoropropene (CF.sub.3CH.dbd.CHF, HFC-1234ze) and
2,3,3,3-tetrafluoropropene (CF.sub.3CF.dbd.CH.sub.2, HFC-1234yf).
The process comprises (a) reacting hydrogen fluoride (HF), chlorine
(Cl.sub.2), and at least one halopropene of the formula
CX.sub.3CCl.dbd.CClX, wherein each X is independently selected from
the group consisting of F and Cl, to produce a product comprising
CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and CF.sub.3CClFCCl.sub.2F
(CFC-215bb), wherein said CF.sub.3CCl.sub.2CClF.sub.2 and
CF.sub.3CClFCCl.sub.2F are produced in the presence of a catalyst
composition comprising chromium, oxygen, and at least two modifier
metals selected from the group consisting of gold, silver, and
palladium as essential constituent elements, wherein the total
amount of modifier metals in said catalyst composition is from
about 0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition; (b)
reacting CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F
produced in (a) with hydrogen (H.sub.2) to produce a product
comprising CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and
CF.sub.3CHFCH.sub.2F (HFC-245eb); (c) dehydrofluorinating
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F produced in (b)
to produce a product comprising CF.sub.3CH.dbd.CHF (HFC-1234ze) and
CF.sub.3CF.dbd.CH.sub.2 (HFC-1234yf); and (d) recovering at least
one compound selected from the group consisting of
CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2 from the product
produced in (c).
D.
[0018] This invention provides a process for the manufacture of
1,1,1,3,3,3-hexafluoropropane (HFC-236fa) and at least one compound
selected from the group consisting of 1,1,1,2,3,3-hexafluoropropane
(HFC-236ea) and hexafluoropropene (HFP, CF.sub.3CF.dbd.CF.sub.2).
The process comprises (a) reacting HF, Cl.sub.2, and at least one
halopropene of the formula CX.sub.3CCl.dbd.CClX; wherein each X is
independently selected from the group consisting of F and Cl, to
produce a product comprising CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2, wherein said CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 are produced in the presence of a catalyst
composition comprising chromium, oxygen, and at least two modifier
metals selected from the group consisting of gold, silver, and
palladium as essential constituent elements, wherein the total
amount of modifier metals in said catalyst composition is from
about 0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition; (b)
reacting CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2
produced in (a) with hydrogen, optionally in the presence of HF, to
produce a product comprising CF.sub.3CH.sub.2CF.sub.3 and at least
one compound selected from the group consisting of
CHF.sub.2CHFCF.sub.3 and CF.sub.3CF.dbd.CF.sub.2; and (c)
recovering from the product produced in (b),
CF.sub.3CH.sub.2CF.sub.3 and at least one compound selected from
the group consisting of CHF.sub.2CHFCF.sub.3 and
CF.sub.3CF.dbd.CF.sub.2.
E.
[0019] This invention provides a process for the manufacture of at
least one compound selected from the group consisting of
1,1,3,3,3-pentafluoropropene (CF.sub.3CH.dbd.CF.sub.2, HFC-1225zc)
and 1,2,3,3,3-pentafluoropropene (CF.sub.3CF.dbd.CHF, HFC-1225ye).
The process comprises (a) reacting HF, Cl.sub.2, and at least one
halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein each X is
independently selected from the group consisting of F and Cl, to
produce a product comprising CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2, wherein said CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 are produced in the presence of a catalyst
composition comprising chromium, oxygen, and at least two modifier
metals selected from the group consisting of gold, silver, and
palladium as essential constituent elements, wherein the total
amount of modifier metals in said catalyst composition is from
about 0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition; (b)
reacting CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2
produced in (a) with hydrogen, optionally in the presence of HF, to
produce a product comprising CF.sub.3CH.sub.2CF.sub.3 and
CF.sub.3CHFCHF.sub.2; (c) dehydrofluorinating
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 produced in (b)
to produce a product comprising CF.sub.3CH.dbd.CF.sub.2 and
CF.sub.3CF.dbd.CHF; and (d) recovering at least one compound
selected from the group consisting of CF.sub.3CH.dbd.CF.sub.2 and
CF.sub.3CF.dbd.CHF from the product produced in (c).
F.
[0020] This invention provides a process for making at least one
compound selected from 1,1,1,3,3-pentafluoropropane (HFC-245fa) and
1,1,1,3,3,3-hexafluoropropane (HFC-236fa). The process comprises
(a) reacting hydrogen fluoride (HF) and at least one halopropene of
the formula CX.sub.3CCl.dbd.CClX, wherein each X is independently
selected from the group consisting of F and Cl, to produce a
product comprising at least one compound selected from
CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc) and CF.sub.3CHClCF.sub.3
(HCFC-226da), wherein said CF.sub.3CCl.dbd.CF.sub.2 and
CF.sub.3CHClCF.sub.3 are produced in the presence of a catalyst
composition comprising chromium, oxygen, and at least two modifier
metals selected from the group consisting of gold, silver, and
palladium as essential constituent elements, wherein the total
amount of modifier metals in said catalyst composition is from
about 0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition; (b)
reacting at least one compound selected from
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 produced in (a)
with hydrogen (H.sub.2), optionally in the presence of HF, to
produce a product comprising at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and CF.sub.3CH.sub.2CF.sub.3
(HFC-236fa); and (c) recovering at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 from the
product produced in (b).
G.
[0021] This invention provides a process for making at least one
compound selected from the group consisting of
1,3,3,3-tetrafluoropropene (CF.sub.3CH.dbd.CHF, HFC-1234ze) and
1,1,3,3,3-pentafluoropropene (CF.sub.3CH.dbd.CF.sub.2, HFC-1225zc).
The process comprises (a) reacting hydrogen fluoride (HF) and at
least one halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein
each X is independently selected from the group consisting of F and
Cl, to produce a product comprising at least one compound selected
from CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc) and
CF.sub.3CHClCF.sub.3, (HCFC-226da), wherein said
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 are produced in
the presence of a catalyst composition comprising chromium, oxygen,
and at least two modifier metals selected from the group consisting
of gold, silver, and palladium as essential constituent elements,
wherein the total amount of modifier metals in said catalyst
composition is from about 0.05 atom % to about 10 atom % based on
the total amount of chromium and modifier metals in the catalyst
composition; (b) reacting at least one compound selected from
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 produced in (a)
with hydrogen (H.sub.2), optionally in the presence of HF, to
produce a product comprising at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and CF.sub.3CH.sub.2CF.sub.3
(HFC-236fa); (c) dehydrofluorinating at least one compound selected
from CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3
produced in (b) to produce a product comprising at least one
compound selected from CF.sub.3CH.dbd.CHF (HFC-1234ze) and
CF.sub.3CH.dbd.CF.sub.2 (HFC-1225zc); and (d) recovering at least
one compound selected from the group consisting of
CF.sub.3CH.dbd.CHF and CF.sub.3CH.dbd.CF.sub.2 from the product
produced in (c).
DETAILED DESCRIPTION
A.
[0022] Invention Category A of this application includes new
catalyst compositions. New catalyst compositions of this invention
comprise chromium, oxygen, modifier metals (e.g., modifier
metal-containing chromium oxide) and contain from about 0.05 atom %
to about 10 atom % modifier metals based on the total amount of
modifier metals and chromium in the catalyst composition. Of note
are compositions comprising silver and gold wherein the mole ratio
of silver to gold is from about 10:1 to about 1:10. Also of note
are compositions comprising silver and palladium wherein the mole
ratio of silver to palladium is from about 10:1 to about 1:10. Also
of note are compositions comprising palladium and gold wherein the
mole ratio of palladium to gold is from about 10:1 to about
1:10.
[0023] In one embodiment of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.alpha.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the zero
oxidation state) and metallic silver (i.e., silver in the zero
oxidation state). In another embodiment of this invention, the
catalyst composition comprises alpha-chromium oxide (i.e.,
.alpha.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the zero
oxidation state) and palladium. In another embodiment of this
invention, the catalyst composition comprises alpha-chromium oxide
(i.e., .alpha.-Cr.sub.2O.sub.3), metallic gold (i.e., gold in the
zero oxidation state), metallic silver (i.e., silver in the zero
oxidation state), and palladium. Of note are embodiments wherein at
least 50 weight % of the chromium component is present as
alpha-chromium oxide. Also of note are embodiments wherein the gold
component consists essentially of metallic gold having an average
particle size of from about 1 nanometer to about 500 nanometers. In
certain embodiments of this invention, particles of metallic gold
and metallic silver and/or palladium are dispersed in a matrix
comprising chromium oxide. In some embodiments particles of
metallic gold and metallic silver and/or palladium are supported on
a chromium oxide support.
[0024] In other embodiments of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.alpha.-Cr.sub.2O.sub.3), metallic silver (i.e., silver in the zero
oxidation state) and palladium. Of note are embodiments wherein at
least 50 weight % of the chromium component is present as
alpha-chromium oxide. In certain embodiments of this invention,
particles of metallic silver and palladium are dispersed in a
matrix comprising chromium oxide. In some embodiments particles of
metallic silver and palladium are supported on a chromium oxide
support.
[0025] The catalyst compositions of this invention may further
comprise fluorine as an essential constituent element.
[0026] The catalyst compositions of the present invention may be
prepared by co-precipitation. The catalyst compositions prepared by
the co-precipitation processes comprise particles of at least two
of metallic gold, metallic silver, and palladium dispersed in a
matrix comprising chromium oxide.
[0027] In a typical co-precipitation technique, an aqueous solution
of soluble modifier metal salts and a soluble chromium salt (e.g.
gold(III) and chromium(III) salts) is prepared. The relative amount
of modifier metal and chromium salts in the aqueous solution is
dictated by the amount of modifier metal relative to chromium
desired in the final catalyst composition. Of note is an aqueous
solution having a modifier metal content of from about 0.05 atom %
to about 10 atom % of the total content of modifier metals and
chromium in the solution. The concentration of chromium salt in the
aqueous solution is typically from about 0.3 to about 3 molar
(moles per liter). Preferred concentration of chromium salt is from
about 0.75 to about 1.5 molar. Chromium salts suitable for
preparation of the aqueous solution are the nitrate, sulfate,
acetate, formate, oxalate, phosphate, bromide, chloride, and
various hydrated forms of these salts. Other suitable chromium
salts include hexacoordinate complexes of the formula
[CrL.sub.6-zA.sub.z].sup.+(3-z) where each L is a neutral (i.e.,
uncharged) ligand selected from the group consisting of H.sub.2O,
NH.sub.3, C.sub.1-C.sub.4 primary, secondary, and tertiary organic
amines, C.sub.1-C.sub.4 alkyl nitrites, and pyridine and its
derivatives. Each A is an anionic ligand selected from the group
consisting of fluoride, chloride, bromide, iodide, hydroxide,
nitrite, and nitrate. Z has a value of from 0 to 3. L can also be
neutral bidentate ligands such as ethylene diamine. In such a
situation, each neutral bidentate ligand is equivalent to two L
ligands since it occupies two coordination sites. A can also be
anionic bidentate ligands such as C.sub.1-C.sub.4 carboxylate. In
such a situation, each anionic bidentate ligand is equivalent to
two A ligands since it occupies two coordination sites. A can also
be dianionic ligands such as sulfates. In such a situation, each
dianionic ligand is equivalent to two A ligands. Such a dianionic
ligand may occupy more than one coordination site.
[0028] Chromium(III)nitrate, or a hydrated form such as
[Cr(NO.sub.3).sub.3(H.sub.2O).sub.9], is the most preferred
chromium salt for the preparation of the aqueous solutions for the
co-precipitation.
[0029] Gold salts suitable for preparation of the aqueous solution
include the acetate, bromide, chloride, and various hydrated forms
of these salts. Gold(III)chloride and hydrogen tetrachloroaurate
(HAuCl.sub.4.3H.sub.2O) are the most preferred gold salts for the
preparation of the aqueous solutions for the co-precipitation.
Suitable silver salts include silver(I)nitrate. Suitable palladium
salts include palladium(II)chloride, tetrachloropalladate salts,
and palladium(II)nitrate.
[0030] The aqueous solution of the soluble modifier metal salts and
soluble chromium salts is then treated with a base such as ammonium
hydroxide (aqueous ammonia) to co-precipitate modifier metals and
chromium salts as the hydroxides. The addition of ammonium
hydroxide to the aqueous solution of modifier metals and chromium
salts is typically carried out gradually over a period of 1 to 12
hours. The pH of the solution is monitored during the addition of
base. The final pH is typically from about 6.0 to about 10.0,
preferably from about 7.5 to about 9.0 and most preferably from
about 8.0 to about 8.7. The co-precipitation of the modifier metal
hydroxides/chromium hydroxide mixture is typically carried out at a
temperature of from about 15.degree. C. to about 60.degree. C.,
preferably from about 20.degree. C. to about 40.degree. C. After
the ammonium hydroxide is added, the mixture is typically stirred
for up to 24 hours.
[0031] After the co-precipitation of the mixture of modifier metal
hydroxides and chromium hydroxide is complete, the co-precipitated
solid is dried. In one embodiment of this invention, the
co-precipitated solid is dried by evaporation. In another
embodiment of this invention, the co-precipitated solid is
collected by filtration and washed with deionized water prior to
drying.
[0032] After the co-precipitated solid has been dried, the solid is
then calcined at temperatures of from about 375.degree. C. to about
1000.degree. C., preferably from about 400.degree. C. to about
900.degree. C., and most preferably from about 400.degree. C. to
about 600.degree. C. for about 12 to 24 hours. The calcination can
be carried out in an atmosphere containing at least 10% oxygen by
volume. Preferably, the calcination is carried out in the presence
of air.
[0033] In one embodiment of this invention, the co-precipitated
solid also contains nitrate salts (e.g. when chromium(III)nitrate
is used as a soluble chromium salt for the co-precipitation). In
such a situation, after the co-precipitated solid has been dried,
but before calcination, the nitrate salts contained in the dried
co-precipitated solid can be decomposed by carefully heating the
solid from about 150.degree. C. to about 350.degree. C.
[0034] The catalyst compositions of the present invention may also
be prepared by impregnating solid chromium oxide with a solution of
soluble modifier metal salts. In this technique, an aqueous
solution of soluble modifier metal salts is added with stirring to
solid chromium oxide. It is preferable to adjust the total volume
of the aqueous modifier metal salt solution so that after addition,
the resulting modifier metal salt-impregnated chromium oxide has a
minimum amount of excess liquid. The entire modifier metal
salt-impregnated chromium oxide, with any excess liquid present, is
dried. In one embodiment of this invention, the entire modifier
metal salt-impregnated chromium oxide, with any excess liquid
present, is dried by evaporation at about 100.degree. C. to
120.degree. C. in air for about 12 hours. The dried solid is then
calcinated at about 200.degree. C. to 400.degree. C. for about 12
to 24 hours. The calcination can be carried out in an atmosphere
containing at least 10% oxygen by volume. Preferably, the
calcination is carried out in the presence of air. The catalyst
compositions prepared by such impregnation processes comprise
particles of at least two of metallic gold, metallic silver, and
palladium supported on a chromium oxide support. The solid chromium
oxide used in the impregnation procedure may be amorphous, partly
crystalline or crystalline.
[0035] The catalyst compositions of the present invention may also
be prepared by mixing multiple compositions, each comprising
chromium, oxygen, and at least one modifier metal (with and without
fluorinating treatment) provided that the final composition
comprises at least two of the modifier metals. By mixing is meant
physically mixing two or more different compositions. Typically,
each composition mixed is in the form of a powder or granulated
material (e.g., pellets). Suitable means of mixing powders and
granulated solids are well known in the art. Examples include
compositions prepared by mixing a composition comprising chromium,
oxygen and gold with a composition comprising chromium, oxygen and
silver; compositions prepared by mixing a composition comprising
chromium, oxygen and gold with a composition comprising chromium,
oxygen and palladium; compositions prepared by mixing a composition
comprising chromium, oxygen and palladium with a composition
comprising chromium, oxygen and silver; compositions prepared by
mixing a composition comprising chromium, oxygen and gold with a
composition comprising chromium, oxygen and silver and a
composition comprising chromium, oxygen and palladium; compositions
prepared by mixing a composition comprising chromium, oxygen, gold
and silver with a composition comprising chromium, oxygen, gold and
palladium; and compositions prepared by mixing a composition
comprising chromium, oxygen, and gold at one concentration and
silver with a composition comprising chromium, oxygen, gold at a
different concentration and silver. Such compositions can be
prepared, for example, by first preparing the selected individual
compositions (e.g., by impregnation or co-precipitation) and mixing
them in a suitable mixing apparatus prior to use as catalysts.
Mixing can be accomplished before or after a calcination step. The
mixture of multiple compositions may be treated with a fluorinating
agent. If a fluorinating treatment is desired, it may be carried
out prior to mixing or after mixing. Of note is a catalyst
composition that comprises a mixture of a composition comprising
chromium, oxygen, gold and silver with a composition comprising
chromium, oxygen, gold and palladium. Also of note is a catalyst
composition that comprises a mixture of a composition comprising
chromium, oxygen, gold and silver with a composition comprising
chromium, oxygen, silver and palladium. Also of note is a catalyst
composition that comprises a mixture of a composition comprising
chromium, oxygen, gold and palladium with a composition comprising
chromium, oxygen, silver and palladium.
[0036] The modifier metal-containing chromium oxide catalysts of
the present invention can be formed into various shapes such as
pellets, granules, and extrudates for use in packing reactors. They
can also be used in powder forms.
[0037] The catalyst compositions of this invention may further
comprise one or more additives in the form of metal compounds. Such
additives may alter the selectivity and/or the activity of the
modifier metal-containing chromium oxide catalyst compositions or
the fluorinated modifier metal-containing chromium oxide catalyst
compositions. Suitable additives can be selected from the group
consisting of the fluorides, oxides, and oxyfluoride compounds of
Mg, Ca, Sc, Y, La, Ti, Zr, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Ni, Pt,
Ce, and Zn.
[0038] The total content of the additive(s) in the catalyst
compositions of the present invention may be from about 0.05 weight
% to about 10 weight % based on the total metal content of the
catalyst compositions. The additives may be incorporated into the
catalyst compositions of the present invention by standard
procedures such as by impregnation or during co-precipitation of
the modifier metal and chromium salts.
[0039] The catalyst compositions of the present invention can be
treated with a fluorinating agent to form catalyst compositions
comprising chromium, oxygen, modifier metals and fluorine as
essential elements. Typically, prior to being used as catalysts,
(e.g. for changing the fluorine distribution of hydrocarbons and/or
halogenated hydrocarbon compounds) the calcined catalyst
compositions of the present invention will be pre-treated with a
fluorinating agent. Typically this fluorinating agent is HF though
other materials may be used such as sulfur tetrafluoride, carbonyl
fluoride, and fluorinated hydrocarbon compounds such as
trichlorofluoromethane, dichlorodifluoromethane,
chlorodifluoromethane, trifluoromethane, and
1,1,2-trichlorotrifluoroethane. This pretreatment can be
accomplished, for example, by placing the catalyst composition in a
suitable container which can also be the reactor to be used to
perform the process in the present invention, and thereafter,
passing HF over the calcined catalyst composition so as to
partially saturate the catalyst composition with HF. This can be
conveniently carried out by passing HF over the catalyst
composition for a period of time, for example, about 0.1 to about
10 hours at a temperature of, for example, about 200.degree. C. to
about 450.degree. C. Nevertheless, this pre-treatment is not
essential.
[0040] The catalyst compositions of the present invention (with and
without fluorinating treatment) can be used for changing the
fluorine distribution in a hydrocarbon and/or a halogenated
hydrocarbon. The fluorine distribution in a hydrocarbon or a
halogenated hydrocarbon can be changed by increasing the fluorine
content of the hydrocarbon or the halogenated hydrocarbon. The
fluorine distribution of a halogenated hydrocarbon can also be
changed by decreasing the fluorine content of the halogenated
hydrocarbon and/or rearranging the placement of fluorine atoms on
the carbon atoms of the halogenated hydrocarbon. Of note are
processes where the fluorine distribution in halogenated
hydrocarbons containing from one to twelve carbon atoms is changed,
particularly processes where the fluorine distribution in
halogenated hydrocarbons containing from one to six carbon atoms is
changed. Also of note are processes where the fluorine content of
hydrocarbons containing from one to twelve carbon atoms is
increased, particularly processes where the fluorine content in
hydrocarbons containing one to six carbon atoms is increased.
Processes for changing the fluorine distribution in halogenated
hydrocarbons include fluorination, chlorofluorination,
isomerization, disproportionation, dehydrofluorination and
chlorodefluorination. The process is characterized by using as the
catalyst a composition comprising chromium, oxygen, and modifier
metals as essential constituent elements (e.g., a composition
comprising chromium, oxygen, gold, silver, and fluorine as
essential constituent elements, a composition comprising chromium,
oxygen, gold, palladium, and fluorine as essential constituent
elements, or a composition comprising chromium, oxygen, palladium,
silver, and fluorine as essential constituent elements). Suitable
catalyst compositions include those comprising chromium oxide and
modifier metals and/or those prepared by treating compositions
comprising chromium oxide and modifier metals with a fluorinating
agent.
[0041] Saturated halogenated hydrocarbons suitable for
fluorination, chlorofluorination, isomerization,
disproportionation, dehydrofluorination and chlorodefluorination
processes of this invention are typically those which have the
formula C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d, wherein n is an
integer from 1 to 6, a is an integer from 0 to 12, b is an integer
from 0 to 4, c is an integer from 0 to 13, d is an integer from 0
to 13, the sum of b, c and d is at least 1 and the sum of a, b, c,
and d is equal to 2n+2, provided that n is at least 2 for
isomerization, and dehydrofluorination processes and n is at least
1 for the disproportionation process, a is at least 1 for
dehydrofluorination processes, b is 0 for chlorodefluorination
processes, b+c is at least 1 for fluorination processes and is 0
for dehydrofluorination processes, a+b+c is at least 1 for
fluorination, chlorofluorination, isomerization, disproportionation
and dehydrofluorination processes and d is at least 1 for
isomerization, disproportionation, dehydrofluorination and
chlorodefluorination processes. Typical unsaturated halogenated
hydrocarbons suitable for fluorination, chlorofluorination,
isomerization, disproportionation, and chlorodefluorination
processes of this invention are those which have the formula
C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h, wherein p is an integer from
2 to 6, e is an integer from 0 to 10, f is an integer from 0 to 2,
g is an integer from 0 to 12, h is an integer from 0 to 11, the sum
of f, g and h is at least 1 and the sum of e, f, g, and h is equal
to 2p, provided that f is 0 for chlorodefluorination processes,
e+f+g is at least 1 for isomerization and disproportionation
processes and h is at least 1 for isomerization, disproportionation
and chlorodefluorination processes. Typical of saturated
hydrocarbons suitable for chlorofluorination are those which have
the formula C.sub.qH.sub.r where q is an integer from 1 to 6 and r
is 2q+2. Typical of unsaturated hydrocarbons suitable for
fluorination and chlorofluorination are those which have the
formula C.sub.iH.sub.j where i is an integer from 2 to 6 and j is
2i.
Fluorination
[0042] Included in this invention is a process for increasing the
fluorine content of a halogenated hydrocarbon compound or an
unsaturated hydrocarbon compound by reacting said compound with
hydrogen fluoride in the vapor phase in the presence of a catalyst
of the present invention. The process is characterized by using as
the catalyst a composition comprising chromium, oxygen, and
modifier metals as essential constituent elements (e.g., a
composition comprising chromium, oxygen, modifier metals, and
fluorine as essential constituent elements). Suitable catalyst
compositions include those comprising chromium oxide and modifier
metals and/or those prepared by treating compositions comprising
chromium oxide and modifier metals with a fluorinating agent. The
catalyst composition may optionally contain additional components
such as additives to alter the activity and/or the selectivity of
the catalyst.
[0043] Halogenated hydrocarbon compounds suitable as starting
materials for the fluorination process of this invention may be
saturated or unsaturated. Saturated halogenated hydrocarbon
compounds suitable for the fluorination processes of this invention
include those of the general formula
C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d, wherein n is an integer from
1 to 6, a is an integer from 0 to 12, b is an integer from 0 to 4,
c is an integer from 0 to 13, d is an integer from 0 to 13, and the
sum of a, b, c, and d is equal to 2n+2, provided that b+c is at
least 1. Unsaturated halogenated hydrocarbon compounds suitable for
the fluorination processes of this invention include those of the
general formula C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h, wherein p is
an integer from 2 to 6, e is an integer from 0 to 10, f is an
integer from 0 to 2, g is an integer from 0 to 12, h is an integer
from 0 to 11, the sum of f, g and h is at least 1 and the sum of e,
f, g, and h is equal to 2p. Unsaturated hydrocarbons suitable for
fluorination are those which have the formula CiHj where i is an
integer from 2 to 6 and j is 2i. The fluorine content of saturated
compounds of the formula C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d,
unsaturated compounds of the formula
C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h and/or unsaturated compounds
of the formula C.sub.iH.sub.j may be increased by reacting said
compounds with HF in the vapor phase in the presence of the
catalyst composition of the present invention described herein.
Such a process is referred to herein as a vapor phase fluorination
reaction.
[0044] Further information on the fluorination of CFC-1213xa and
further reaction of products obtained from the fluorination
reaction is provided in U.S. Patent Applications 60/927,843 and
60/927,842 [FL-1362 US PRV and FL-1363 US PRV] filed May 4, 2007
and hereby incorporated by reference herein in their entirety.
[0045] The vapor phase fluorination reactions are typically
conducted at temperatures of from about 150.degree. C. to
500.degree. C. For saturated compounds the fluorination is
preferably carried out from about 175.degree. C. to 400.degree. C.
and more preferably from about 200.degree. C. to about 350.degree.
C. For unsaturated compounds the fluorination is preferably carried
out from about 150.degree. C. to 350.degree. C. and more preferably
from about 175.degree. C. to about 300.degree. C.
[0046] The vapor phase fluorination reactions are typically
conducted at atmospheric and superatmospheric pressures. For
reasons of convenience in downstream separation processes (e.g.,
distillation), pressures of up to about 30 atmospheres may be
employed.
[0047] The vapor phase fluorination reactions are typically
conducted in a tubular reactor. The reactor and its associated feed
lines, effluent lines, and associated units should be constructed
of materials resistant to hydrogen fluoride and hydrogen chloride.
Typical materials of construction, well-known to the fluorination
art, include stainless steels, in particular of the austenitic
type, the well-known high nickel alloys, such as Monel.RTM.
nickel-gold alloys, Hastelloy.RTM. nickel-based alloys and,
Inconel.RTM. nickel-chromium alloys, and gold-clad steel.
[0048] The contact time in the reactor is typically from about 1 to
about 120 seconds. Of note are contact times of from about 5 to
about 60 seconds.
[0049] The amount of HF reacted with the unsaturated hydrocarbons
or halogenated hydrocarbon compounds should be at least a
stoichiometric amount. The stoichiometric amount is based on the
number of Br and/or Cl substituents to be replaced by F in addition
to one mole of HF to saturate the carbon-carbon double bond if
present. Typically, the molar ratio of HF to the said compounds of
the formulas C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d,
C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h, and C.sub.iH.sub.j can range
from about 0.5:1 to about 100:1, preferably from about 2:1 to about
50:1, and more preferably from about 3:1 to about 20:1. In general,
with a given catalyst composition, the higher the temperature and
the longer the contact time, the greater is the conversion to
fluorinated products. The above variables can be balanced, one
against the other, so that the formation of higher fluorine
substituted products is maximized.
[0050] Examples of saturated compounds of the formula
C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d which may be reacted with HF
in the presence of the catalyst of this invention include
CH.sub.2Cl.sub.2, CH.sub.2Br.sub.2, CHCl.sub.3, CCl.sub.4,
CBr.sub.4, C.sub.2Cl.sub.6, C.sub.2BrCl.sub.5, C.sub.2Cl.sub.5F,
C.sub.2Cl.sub.4F.sub.2, C.sub.2Cl.sub.3F.sub.3,
C.sub.2Cl.sub.2F.sub.4, C.sub.2ClF.sub.5, C.sub.2HCl.sub.5,
C.sub.2HCl.sub.4F, C.sub.2HCl.sub.3F.sub.2,
C.sub.2HCl.sub.2F.sub.3, C.sub.2HClF.sub.4, C.sub.2HBrF.sub.4,
C.sub.2H.sub.2Cl.sub.4, C.sub.2H.sub.2Cl.sub.3F,
C.sub.2H.sub.2Cl.sub.2F.sub.2, C.sub.2H.sub.2ClF.sub.3,
C.sub.2H.sub.3Cl.sub.3, C.sub.2H.sub.3Cl.sub.2F,
C.sub.2H.sub.3ClF.sub.2, C.sub.2H.sub.4Cl.sub.2, C.sub.2H.sub.4ClF,
C.sub.3Cl.sub.6F.sub.2, C.sub.3Cl.sub.5F.sub.3,
C.sub.3Cl.sub.4F.sub.4, C.sub.3Cl.sub.3F.sub.5, C.sub.3HCl.sub.7,
C.sub.3HCl.sub.6F, C.sub.3HCl.sub.5F.sub.2,
C.sub.3HCl.sub.4F.sub.3, C.sub.3HCl.sub.3F.sub.4,
C.sub.3HCl.sub.2F.sub.5, C.sub.3H.sub.2Cl.sub.6,
C.sub.3H.sub.2BrCl.sub.5, C.sub.3H.sub.2Cl.sub.5F,
C.sub.3H.sub.2Cl.sub.4F.sub.2, C.sub.3H.sub.2Cl.sub.3F.sub.3,
C.sub.3H.sub.2Cl.sub.2F.sub.4, C.sub.3H.sub.2ClF.sub.5,
C.sub.3H.sub.3Cl.sub.5, C.sub.3H.sub.3Cl.sub.4F,
C.sub.3H.sub.3Cl.sub.3F.sub.2, C.sub.3H.sub.3Cl.sub.2F.sub.3,
C.sub.3H.sub.3ClF.sub.4, C.sub.3H.sub.4Cl.sub.4,
C.sub.4H.sub.6Cl.sub.4, C.sub.4H.sub.4Cl.sub.6,
C.sub.4H.sub.5Cl.sub.5, C.sub.4H.sub.5Cl.sub.4F,
C.sub.4H.sub.4Cl.sub.3F.sub.3, C.sub.4H.sub.4Cl.sub.4F.sub.2,
C.sub.4H.sub.4Cl.sub.5F, C.sub.5H.sub.2Cl.sub.4F.sub.6,
C.sub.5H.sub.2Cl.sub.5F.sub.5, C.sub.5H.sub.3Cl.sub.4F.sub.5,
C.sub.5H.sub.3Cl.sub.5F.sub.4, and C.sub.5H.sub.4Cl.sub.8.
[0051] Specific examples of vapor phase fluorination reactions of
saturated halogenated hydrocarbon compounds which may be carried
out under the conditions described above using the catalysts of
this invention include the conversion of CH.sub.2Cl.sub.2 to
CH.sub.2F.sub.2, the conversion of CHCl.sub.3 to a mixture of
CHCl.sub.2F, CHClF.sub.2, and CHF.sub.3, the conversion of
CH.sub.3CHCl.sub.2 to a mixture of CH.sub.3CHClF and
CH.sub.3CHF.sub.2, the conversion of CH.sub.2ClCH.sub.2Cl to a
mixture of CH.sub.3CHClF and CH.sub.3CHF.sub.2, the conversion of
CH.sub.3CCl.sub.3 to a mixture of CH.sub.3CCl.sub.2F,
CH.sub.3CClF.sub.2, and CH.sub.3CF.sub.3, the conversion of
CH.sub.2ClCF.sub.3 to CH.sub.2FCF.sub.3, the conversion of
CHCl.sub.2CF.sub.3 to a mixture of CHClFCF.sub.3 and
CHF.sub.2CF.sub.3, the conversion of CHClFCF.sub.3 to
CHF.sub.2CF.sub.3, the conversion of CHBrFCF.sub.3 to
CHF.sub.2CF.sub.3, the conversion of CCl.sub.3CF.sub.2CCl.sub.3 to
a mixture of CCl.sub.2FCF.sub.2CClF.sub.2 and
CClF.sub.2CF.sub.2CClF.sub.2, the conversion of
CCl.sub.3CH.sub.2CCl.sub.3 to CF.sub.3CH.sub.2CClF.sub.2 and
CF.sub.3CH.sub.2CF.sub.3, the conversion of
CCl.sub.3CH.sub.2CHCl.sub.2 to a mixture of
CF.sub.3CH.sub.2CHF.sub.2, CF.sub.3CH.dbd.CHCl, and
CF.sub.3CH.dbd.CHF, the conversion of CF.sub.3CCl.sub.2CClF.sub.2
to a mixture of CF.sub.3CCl.sub.2CF.sub.3, and
CF.sub.3CClFCF.sub.3, the conversion of CF.sub.3CCl.sub.2CF.sub.3
to CF.sub.3ClFCF.sub.3, and the conversion of a mixture comprising
CF.sub.3CF.sub.2CHCl.sub.2 and CClF.sub.2CF.sub.2CHClF to a mixture
of CF.sub.3CF.sub.2CHClF and CF.sub.3CF.sub.2CHF.sub.2.
[0052] Examples of unsaturated compounds of the formula
C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h and C.sub.iH.sub.j which may
be reacted with HF in the presence of the catalysts of this
invention include C.sub.2Cl.sub.4, C.sub.2BrCl.sub.3,
C.sub.2Cl.sub.3F, C.sub.2Cl.sub.2F.sub.2, C.sub.2ClF.sub.3,
C.sub.2F.sub.4, C.sub.2HCl.sub.3, C.sub.2HBrCl.sub.2,
C.sub.2HCl.sub.2F, C.sub.2HClF.sub.2, C.sub.2HF.sub.3,
C.sub.2H.sub.2Cl.sub.2, C.sub.2H.sub.2ClF, C.sub.2H.sub.2F.sub.2,
C.sub.2H.sub.3C.sub.1, C.sub.2H.sub.3F, C.sub.2H.sub.4,
C.sub.3H.sub.6, C.sub.3H.sub.5C.sub.1, C.sub.3H.sub.4Cl.sub.2,
C.sub.3H.sub.3Cl.sub.3, C.sub.3H.sub.2Cl.sub.4, C.sub.3HCl.sub.5,
C.sub.3Cl.sub.6, C.sub.3Cl.sub.5F, C.sub.3Cl.sub.4F.sub.2,
C.sub.3Cl.sub.3F.sub.3, C.sub.3Cl.sub.2F.sub.4, C.sub.3ClF.sub.5,
C.sub.3HF.sub.5, C.sub.3H.sub.2F.sub.4, C.sub.3F.sub.6,
C.sub.4Cl.sub.8, C.sub.4Cl.sub.2F.sub.6, C.sub.4ClF.sub.7,
C.sub.4H.sub.2F.sub.6, C.sub.4H.sub.2ClF.sub.5,
C.sub.4H.sub.2Cl.sub.2F.sub.4, C.sub.4H.sub.2Cl.sub.3F.sub.3,
C.sub.4HClF.sub.6 and C.sub.5H.sub.2Cl.sub.4F.sub.5.
[0053] Specific examples of vapor phase fluorination reactions of
unsaturated halogenated hydrocarbon compounds which may be carried
out using the catalysts of this invention include the conversion of
CHCl.dbd.CCl.sub.2 to a mixture of CH.sub.2ClCF.sub.3 and
CH.sub.2FCF.sub.3, the conversion of CCl.sub.2.dbd.CCl.sub.2 to a
mixture of CHCl.sub.2CF.sub.3, CHClFCF.sub.3, and
CHF.sub.2CF.sub.3, the conversion of CCl.sub.2.dbd.CH.sub.2 to a
mixture of CH.sub.3CCl.sub.2F, CH.sub.3CClF.sub.2, and
CH.sub.3CF.sub.3, the conversion of CH.sub.2.dbd.CHCl to a mixture
of CH.sub.3CHClF and CH.sub.3CHF.sub.2, the conversion of
CF.sub.2.dbd.CH.sub.2 to CH.sub.3CF.sub.3, the conversion of
CCl.sub.2.dbd.CClCF.sub.3 to a mixture of CF.sub.3CHClCClF.sub.2,
CF.sub.3CHClCF.sub.3, and/or CF.sub.3CCl.dbd.CF.sub.2, the
conversion of CF.sub.3CF.dbd.CF.sub.2 to CF.sub.3CHFCF.sub.3, the
conversion of CF.sub.3CH.dbd.CF.sub.2 to CF.sub.3CH.sub.2CF.sub.3,
and the conversion of CF.sub.3CH.dbd.CHF to
CF.sub.3CH.sub.2CHF.sub.2.
[0054] Of note is a catalytic process for producing a mixture of
2-chloro-1,1,1,3,3,3-hexafluoropropane (i.e., CF.sub.3CHClCF.sub.3
or HCFC-226da) and 2-chloro-pentafluoropropene (i.e.,
CF.sub.3CCl.dbd.CF.sub.2 or CFC-1215xc) by the vapor phase
fluorination reactions of a hexahalopropene of the formula
C.sub.3Cl.sub.6-xF.sub.x, wherein x equals 0 to 4. Preferred
hexahalopropenes of the formula C.sub.3Cl.sub.6-xF.sub.x include
1,1,2-trichloro-3,3,3-trifluoro-1-propene (i.e.,
CCl.sub.2.dbd.CClCF.sub.3 or CFC-1213xa) and hexachloropropene
(i.e., CCl.sub.2.dbd.CClCCl.sub.3). The mixture of HCFC-226da and
CFC-1215xc is produced by reacting the above unsaturated compounds
with HF in the vapor phase in the presence of the catalysts of this
invention at temperatures from about 150.degree. C. to about
400.degree. C., preferably from about 200.degree. C. to about
350.degree. C. The amount of HF fed to the reactor should be at
least a stoichiometric amount as define above. In the case of
fluorination of CFC-1213xa to a mixture of HCFC-226da and
CFC-1215xc, the stoichiometric ratio of HF to CFC-1213xa is 3:1.
Preferred ratios of HF to C.sub.3Cl.sub.6-xF.sub.x starting
material(s) are typically in the range of from about the
stoichiometric ratio to about 25:1. Preferred contact times are
typically in the range of from 1 to 60 seconds.
[0055] Mixtures of saturated halogenated hydrocarbon compounds or
mixtures of unsaturated hydrocarbons and/or halogenated hydrocarbon
compounds may also be used in the vapor phase fluorination
reactions as well as mixtures comprising both unsaturated
hydrocarbons and halogenated hydrocarbon compounds. Specific
examples of mixtures of saturated halogenated hydrocarbon compounds
and mixtures of unsaturated hydrocarbons and unsaturated
halogenated hydrocarbon compounds that may be subjected to vapor
phase fluorination using the catalysts of this invention include a
mixture of CH.sub.2Cl.sub.2 and CCl.sub.2.dbd.CCl.sub.2, a mixture
of CCl.sub.2FCClF.sub.2 and CCl.sub.3CF.sub.3, a mixture of
CCl.sub.2.dbd.CCl.sub.2 and CCl.sub.2.dbd.CClCCl.sub.3, a mixture
of CH.sub.2.dbd.CHCH.sub.3 and CH.sub.2.dbd.CClCH.sub.3, a mixture
of CH.sub.2Cl.sub.2 and CH.sub.3CCl.sub.3, a mixture of
CHF.sub.2CClF.sub.2 and CHClFCF.sub.3, a mixture of
CHCl.sub.2CCl.sub.2CH.sub.2Cl and CCl.sub.3CHClCH.sub.2Cl, a
mixture of CHCl.sub.2CH.sub.2CCl.sub.3 and CCl.sub.3CHClCH.sub.2Cl,
a mixture of CHCl.sub.2CHClCCl.sub.3, CCl.sub.3CH.sub.2CCl.sub.3,
and CCl.sub.3CCl.sub.2CH.sub.2Cl, a mixture of
CHCl.sub.2CH.sub.2CCl.sub.3 and CCl.sub.3CH.sub.2CCl.sub.3, a
mixture of and CF.sub.3CH.sub.2CCl.sub.2F and
CF.sub.3CH.dbd.CCl.sub.2, and a mixture of CF.sub.3CH.dbd.CHCl and
CF.sub.3CH.dbd.CCl.sub.2.
Chlorofluorination
[0056] Included in this invention is a process for increasing the
fluorine content of a halogenated hydrocarbon compound or a
hydrocarbon compound by reacting said compound with hydrogen
fluoride (HF) and chlorine (Cl.sub.2) in the vapor phase in the
presence of a catalyst. The process is characterized by using as
the catalyst a composition comprising chromium, oxygen, and
modifier metals as essential constituent elements (e.g., a
composition comprising chromium, oxygen, modifier metals, and
fluorine as essential constituent elements). Suitable catalyst
compositions include those comprising chromium oxide and modifier
metals and/or those prepared by treating compositions comprising
chromium oxide and modifier metals with a fluorinating agent. The
catalyst composition may optionally contain additional components
such as additives to alter the activity and/or the selectivity of
the catalyst.
[0057] Halogenated hydrocarbon compounds suitable as starting
materials for the chlorofluorination process of this invention may
be saturated or unsaturated. Saturated halogenated hydrocarbon
compounds suitable for the chlorofluorination processes of this
invention include those of the general formula
C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d, wherein n is an integer from
1 to 6, a is an integer from 0 to 12, b is an integer from 0 to 4,
c is an integer from 0 to 13, d is an integer from 0 to 13, the sum
of b, c and d is at least 1 and the sum of a, b, c, and d is equal
to 2n+2, provided that a+b+c is at least 1. Preferred
chlorofluorination processes include those involving said saturated
starting materials where a is at least 1. Saturated hydrocarbon
compounds suitable for chlorofluorination are those which have the
formula C.sub.qH.sub.r where q is an integer from 1 to 6 and r is
2q+2. Unsaturated halogenated hydrocarbon compounds suitable for
the chlorofluorination processes of this invention include those of
the general formula C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h, wherein
p is an integer from 2 to 6, e is an integer from 0 to 10, f is an
integer from 0 to 2, g is an integer from 0 to 12, h is an integer
from 0 to 11, the sum of f, g and h is at least 1 and the sum of e,
f, g, and h is equal to 2p. Unsaturated hydrocarbon compounds
suitable for fluorination are those which have the formula
C.sub.iH.sub.j where i is an integer from 2 to 6 and j is 2i. The
fluorine content of saturated compounds of the formula
C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d and C.sub.qH.sub.r and/or
unsaturated compounds of the formula
C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h and C.sub.iH.sub.j may be
increased by reacting said compounds with HF and Cl.sub.2 in the
vapor phase in the presence of a catalyst mentioned herein. Such a
process is referred to herein as a vapor phase chlorofluorination
reaction.
[0058] The conditions of the vapor phase chlorofluorination
reactions are similar to those described above for vapor phase
fluorination reactions in terms of the temperature ranges, contact
times, pressures, and mole ratios of HF to the halogenated
hydrocarbon compounds. The amount of chlorine (Cl.sub.2) fed to the
reactor is based on whether the halogenated hydrocarbon compounds
fed to the reactor is unsaturated and the number of hydrogens in
C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d, C.sub.qH.sub.r,
C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h, and C.sub.iH.sub.j that are
to be replaced by chlorine and fluorine. One mole of Cl.sub.2 is
required to saturate a carbon-carbon double bond and a mole of
Cl.sub.2 is required for each hydrogen to be replaced by chlorine
or fluorine. A slight excess of chlorine over the stoichiometric
amount may be necessary for practical reasons, but large excesses
of chlorine will result in complete chlorofluorination of the
products. The ratio of Cl.sub.2 to halogenated hydrocarbon compound
is typically from about 1:1 to about 10:1.
[0059] Specific examples of vapor phase chlorofluorination
reactions of saturated halogenated hydrocarbon compounds of the
general formula C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d and saturated
hydrocarbon compounds of the general formula C.sub.qH.sub.r which
may be carried out using the catalysts of this invention include
the conversion of C.sub.2H.sub.6 to a mixture containing
CH.sub.2ClCF.sub.3, the conversion of CH.sub.2ClCF.sub.3 to a
mixture of CHClFCF.sub.3 and CHF.sub.2CF.sub.3, the conversion of
CCl.sub.3CH.sub.2CH.sub.2Cl to a mixture of
CF.sub.3CCl.sub.2CClF.sub.2, CF.sub.3CCl.sub.2CF.sub.3,
CF.sub.3CClFCClF.sub.2, and CF.sub.3CClFCF.sub.3, the conversion of
CCl.sub.3CH.sub.2CHCl.sub.2 to a mixture of
CF.sub.3CCl.sub.2CClF.sub.2, CF.sub.3CCl.sub.2CF.sub.3,
CF.sub.3CClFCClF.sub.2, and CF.sub.3CClFCF.sub.3, the conversion of
CCl.sub.3CHClCH.sub.2Cl to a mixture of
CF.sub.3CCl.sub.2CClF.sub.2, CF.sub.3CCl.sub.2CF.sub.3,
CF.sub.3CClFCClF.sub.2, and CF.sub.3CClFCF.sub.3, the conversion of
CHCl.sub.2CCl.sub.2CH.sub.2Cl to a mixture of
CF.sub.3CCl.sub.2CClF.sub.2, CF.sub.3CCl.sub.2CF.sub.3,
CF.sub.3CClFCClF.sub.2, and CF.sub.3CClFCF.sub.3, the conversion of
CCl.sub.3CH.sub.2CH.sub.2Cl to a mixture of
CF.sub.3CCl.sub.2CHF.sub.2, CF.sub.3CClFCHF.sub.2,
CF.sub.3CClFCClF.sub.2, and CF.sub.3CCl.sub.2CF.sub.3, and the
conversion of CCl.sub.3CH.sub.2CHCl.sub.2 to a mixture of
CF.sub.3CCl.sub.2CHF.sub.2, CF.sub.3CClFCHF.sub.2,
CF.sub.3CClFCClF.sub.2, and CF.sub.3CCl.sub.2CF.sub.3.
[0060] Specific examples of vapor phase chlorofluorination
reactions of unsaturated halogenated hydrocarbon compounds of the
general formula C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h and
unsaturated hydrocarbon compounds of the general formula
C.sub.iH.sub.j which may be carried out using the catalysts of this
invention include the conversion of C.sub.2H.sub.4 to a mixture of
CCl.sub.3CClF.sub.2, CCl.sub.2FCCl.sub.2F, CClF.sub.2CCl.sub.2F,
CCl.sub.3CF.sub.3, CF.sub.3CCl.sub.2F, and CClF.sub.2CClF.sub.2,
the conversion of C.sub.2Cl.sub.4 to a mixture of
CCl.sub.3CClF.sub.2, CCl.sub.2FCCl.sub.2F, CClF.sub.2CCl.sub.2F,
CCl.sub.3CF.sub.3, CF.sub.3CCl.sub.2F, and CClF.sub.2CClF.sub.2,
and the conversion of C.sub.3H.sub.6 or CF.sub.3CCl.dbd.CCl.sub.2
to a mixture of CF.sub.3CCl.sub.2CClF.sub.2,
CF.sub.3CCl.sub.2CF.sub.3, CF.sub.3CClFCClF.sub.2, and
CF.sub.3CClFCF.sub.3.
[0061] Of note is a catalytic process for producing a mixture of
1,2,2-trichloro-1,1,3,3,3-pentafluoropropane (i.e.,
CClF.sub.2CCl.sub.2CF.sub.3 or CFC-215aa),
1,1,2-trichloro-1,2,3,3,3-pentafluoropropane (i.e.,
CCl.sub.2FCClFCF.sub.3 or CFC-215bb),
2,2-dichloro-1,1,1,3,3,3-hexafluoropropane (i.e.,
CF.sub.3CCl.sub.2CF.sub.3 or CFC-216aa),
1,2-dichloro-1,1,1,3,3,3-hexafluoropropane (i.e.,
CClF.sub.2CClFCF.sub.3 or CFC-216ba), and
2-chloro-1,1,1,2,3,3,3-heptafluoropropane (i.e.,
CF.sub.3CClFCF.sub.3 or CFC-217ba), by the chlorofluorination of a
hexahalopropene of the formula C.sub.3Cl.sub.6-xF.sub.x, wherein x
equals 0 to 4. Preferred hexahalopropenes of the formula
C.sub.3Cl.sub.6-xF.sub.x include
1,1,2-trichloro-3,3,3-trifluoro-1-propene (i.e.,
CCl.sub.2.dbd.CClCF.sub.3 or CFC-1213xa) and hexachloropropene
(i.e., CCl.sub.2.dbd.CClCCl.sub.3). The mixture of CFC-215aa,
-215bb, -216aa, -216ba, and -217ba is produced by reacting the
above unsaturated compounds with Cl.sub.2 and HF in the vapor phase
in the presence of the catalysts of this invention at temperatures
from about 150.degree. C. to about 450.degree. C., preferably about
250.degree. C. to 400.degree. C.
[0062] The amount of HF fed to the reactor should be at least a
stoichiometric amount as defined above. In the case of
chlorofluorination of CFC-1213xa to a mixture of
chlorofluoropropanes having an average number of fluorine
substituents of six, the stoichiometric ratio of HF to CFC-1213xa
is 3:1. Preferred ratios of HF to C.sub.3Cl.sub.6-xF.sub.x starting
material(s) are typically in the range of from about the
stoichiometric ratio to about 30:1, more preferably from about 8:1
to about 25:1.
[0063] The amount of chlorine fed to the reactor should be at least
one mole of chlorine per mole of hexahalopropene fed to the
reactor. Preferred molar ratios of Cl.sub.2 to CFC-1213xa are from
about 1:1 to about 5:1. Of note are contact times of from about 5
seconds to about 60 seconds.
[0064] Further information on the chlorofluorination of CFC-1213xa
and further reaction of products obtained from the
chlorofluorination reaction is provided in U.S. Patent Applications
60/927,839, 60/927,848, 60/927,838 and 60/927,847 [FL-1364 US PRV,
FL-1365 US PRV, FL-1366 US PRV, and FL-1367 US PRV] filed May 4,
2007, all hereby incorporated by reference herein in their
entirety.
[0065] Mixtures of saturated hydrocarbon compounds and saturated
halogenated hydrocarbon compounds and mixtures of unsaturated
hydrocarbon compounds and unsaturated halogenated hydrocarbon
compounds as well as mixtures comprising both saturated and
unsaturated compounds may be chlorofluorinated using the catalysts
of the present invention. Specific examples of mixtures of
saturated and unsaturated hydrocarbons and halogenated hydrocarbons
that may be used include a mixture of CCl.sub.2.dbd.CCl.sub.2 and
CCl.sub.2.dbd.CClCCl.sub.3, a mixture of
CHCl.sub.2CCl.sub.2CH.sub.2Cl and CCl.sub.3CHClCH.sub.2Cl, a
mixture of CHCl.sub.2CH.sub.2CCl.sub.3 and CCl.sub.3CHClCH.sub.2Cl,
a mixture of CHCl.sub.2CHClCCl.sub.3, CCl.sub.3CH.sub.2CCl.sub.3,
and CCl.sub.3CCl.sub.2CH.sub.2Cl, a mixture of
CHF.sub.2CH.sub.2CF.sub.3 and CHCl.dbd.CHCF.sub.3, and a mixture of
CH.sub.2.dbd.CH.sub.2 and CH.sub.2.dbd.CHCH.sub.3.
Isomerization and Disproportionation
[0066] Included in this invention is a process for changing the
fluorine distribution in a halogenated hydrocarbon compound by
isomerizing said halogenated hydrocarbon compound in the presence
of a catalyst. The process is characterized by using as the
catalyst a composition comprising chromium, oxygen, and modifier
metals as essential constituent elements (e.g., a composition
comprising chromium, oxygen, modifier metals, and fluorine as
essential constituent elements). Suitable catalyst compositions
include those comprising chromium oxide and modifier metals and/or
those prepared by treating compositions comprising chromium oxide
and modifier metals with a fluorinating agent. The catalyst
composition may optionally contain additional components such as
additives to alter the activity and/or the selectivity of the
catalyst.
[0067] Also included in this invention is a process for changing
the fluorine distribution in a halogenated hydrocarbon compound by
disproportionating said halogenated hydrocarbon compound in the
vapor phase in the presence of a catalyst. The process is
characterized by using as the catalyst a composition comprising
chromium oxide and modifier metals and/or a chromium-containing
catalyst composition prepared by treating said composition
comprising chromium oxide and modifier metals with a fluorinating
agent. The catalyst composition may optionally contain additional
components such as additives to alter the activity and/or the
selectivity of the catalyst.
[0068] Halogenated hydrocarbon compounds suitable as starting
materials for the isomerization and disproportionation processes of
this invention may be saturated or unsaturated. Saturated
halogenated hydrocarbon compounds suitable for the isomerization
and disproportionation processes of this invention include those of
the general formula C.sub.nH.sub.aBr.sub.bCl.sub.cF.sub.d, wherein
n is an integer from 2 to 6, a is an integer from 0 to 12, b is an
integer from 0 to 4, c is an integer from 0 to 13, d is an integer
from 1 to 13, and the sum of a, b, c, and d is equal to 2n+2,
provided that a+b+c is at least 1. Unsaturated halogenated
hydrocarbon compounds suitable for the isomerization and
disproportionation processes of this invention include those of the
general formula C.sub.pH.sub.eBr.sub.fCl.sub.gF.sub.h, wherein p is
an integer from 2 to 6, e is an integer from 0 to 10, f is an
integer from 0 to 2, g is an integer from 0 to 12, h is an integer
from 1 to 11, and the sum of e, f, g, and h is equal to 2p,
provided that the sum of e+f+g is at least 1.
[0069] In one embodiment of the present invention, the fluorine
distribution of a halogenated hydrocarbon compound is changed by
rearranging the H, Br, Cl, and F substituents in the molecule
(typically to a thermodynamically preferred arrangement) while
maintaining the same number of the H, Br, Cl, and F substituents,
respectively. This process is referred to herein as
isomerization.
[0070] In another embodiment of the present invention, the fluorine
distribution of a halogenated hydrocarbon compound is changed by
exchanging at least one F substituent of the halogenated
hydrocarbon starting material with at least one H, Br and/or Cl
substituent of another molecule of the halogenated hydrocarbon
starting material so as to result in the formation of one or more
halogenated hydrocarbon compounds having a decreased fluorine
content compared to the halogenated hydrocarbon starting material
and one or more halogenated hydrocarbon compounds having an
increased fluorine content compared to the halogenated hydrocarbon
starting material. This process is referred to herein as
disproportionation.
[0071] In another embodiment of the present invention, both
isomerization and disproportionation reactions may occur
simultaneously.
[0072] The isomerization and disproportionation (see
disproportionation paragraph below) reactions are typically
conducted at temperatures of from about 150.degree. C. to
500.degree. C., preferably from about 200.degree. C. to about
400.degree. C. The contact time in the reactor is typically from
about 1 to about 120 seconds and preferably from about 5 to about
60 seconds. The isomerization and disproportionation reactions may
be carried out in the presence of an inert gas such as helium,
argon, or nitrogen though this is not preferred. The isomerization
and disproportionation reactions may be carried out in the presence
of HF and HCl, but this is not preferred.
[0073] Specific examples of vapor phase isomerization reactions
which may be carried out using the catalysts of this invention
include the conversion of CClF.sub.2CCl.sub.2F to
CCl.sub.3CF.sub.3, the conversion of CClF.sub.2CClF.sub.2 to
CF.sub.3CCl.sub.2F, the conversion of CHF.sub.2CClF.sub.2 to
CF.sub.3CHClF, the conversion of CHF.sub.2CHF.sub.2 to
CF.sub.3CH.sub.2F, the conversion of CF.sub.3CClFCClF.sub.2 to
CF.sub.3CCl.sub.2CF.sub.3, and the conversion of
CF.sub.3CHFCHF.sub.2 to CF.sub.3CH.sub.2CF.sub.3.
[0074] Specific examples of vapor phase disproportionation
reactions which may be carried out using the catalysts of this
invention include the conversion of CClF.sub.2CClF.sub.2 to a
mixture of CClF.sub.2CCl.sub.2F, CCl.sub.3CF.sub.3, and
CF.sub.3CClF.sub.2, and the conversion of CHClFCF.sub.3 to a
mixture of CHCl.sub.2CF.sub.3, and CHF.sub.2CF.sub.3.
[0075] Of note is a process for the conversion of a mixture of
2-chloro-1,1,2,2-tetrafluoroethane (i.e., CHF.sub.2CClF.sub.2 or
HCFC-124a) and 2-chloro-1,1,1,2-tetrafluoroethane (i.e.,
CF.sub.3CHClF or HCFC-124) to a mixture comprising
2,2-dichloro-1,1,1-trifluoroethane (i.e., CHCl.sub.2CF.sub.3 or
HCFC-123) and 1,1,1,2,2-pentafluoroethane (i.e., CF.sub.3CHF.sub.2
or HFC-125) in addition to unconverted starting materials. The
mixture comprising HFC-125 and HCFC-123 may be obtained in the
vapor phase by contacting a mixture of HCFC-124a and -124 over the
catalysts of this invention optionally in the presence of a diluent
selected from the group consisting of HF, HCl, nitrogen, helium,
argon, and carbon dioxide. If used, the diluent gas, may be present
in a molar ratio of diluent to haloethane of from about 1:1 to
about 5:1.
Dehydrofluorination
[0076] Included in this invention is a process for decreasing the
fluorine content of a halogenated hydrocarbon compound by
dehydrofluorinating said halogenated hydrocarbon compound in the
presence of a catalyst. The process is characterized by using as
the catalyst a composition comprising chromium, oxygen, and
modifier metals as essential constituent elements (e.g., a
composition comprising chromium, oxygen, modifier metals, and
fluorine as essential constituent elements). Suitable catalyst
compositions include those comprising chromium oxide and modifier
metals and/or those prepared by treating compositions comprising
chromium oxide and modifier metals with a fluorinating agent. The
catalyst composition may optionally contain additional components
such as additives to alter the activity and/or the selectivity of
the catalyst.
[0077] Halogenated hydrocarbon compounds suitable as starting
materials for the dehydrofluorination process of this invention are
typically saturated. Saturated halogenated hydrocarbon compounds
suitable for the dehydrofluorination processes of this invention
include those of the general formula C.sub.nH.sub.aF.sub.d, wherein
n is an integer from 2 to 6, a is an integer from 1 to 12, d is an
integer from 1 to 13, and the sum of a and d is equal to 2n+2. The
fluorine content of saturated compounds of the formula
C.sub.nH.sub.aF.sub.d may be decreased in the presence of catalysts
of the present invention. This decrease in fluorine content is
typically associated with removal of hydrogen fluoride (HF) from
the molecule and is referred to herein as dehydrofluorination.
[0078] The dehydrofluorination reactions are typically conducted at
temperatures of from about 200.degree. C. to about 500.degree. C.,
preferably from about 300.degree. C. to about 450.degree. C. The
contact time in the reactor is typically from about 1 to about 360
seconds. Of note are contact times of from about 5 to about 120
seconds. Carrying out the dehydrofluorination reactions in the
presence of an inert gas such as helium, argon, or nitrogen
promotes the dissociation of the fluorinated carbon compound, but
this practice can also lead to difficulties in separation and is
not preferred. The product of dehydrofluorination reaction consists
of HF and the unsaturated fluorinated carbon compound resulting
from loss of HF from the starting material.
[0079] Specific examples of vapor phase dehydrofluorination
reactions which may be carried out using the catalysts of this
invention include the conversion of CH.sub.3CHF.sub.2 to
CH.sub.2.dbd.CHF, the conversion of CH.sub.3CF.sub.3 to
CH.sub.2.dbd.CF.sub.2, the conversion of CF.sub.3CH.sub.2F to
CF.sub.2.dbd.CHF, the conversion of CHF.sub.2CH.sub.2CF.sub.3 to
CHF.dbd.CHCF.sub.3, the conversion of CHF.sub.2CHFCF.sub.3 to
CHF.dbd.CFCF.sub.3, the conversion of CH.sub.3CF.sub.2CF.sub.3 to
CH.sub.2.dbd.CFCF.sub.3, the conversion of
CH.sub.2FCF.sub.2CF.sub.3 to CHF.dbd.CFCF.sub.3, and the conversion
of CF.sub.3CH.sub.2CF.sub.3 to CF.sub.3CH.dbd.CF.sub.2.
[0080] Of note is a catalytic process for producing fluoroethene
(i.e., CH.sub.2.dbd.CHF or vinyl fluoride) by the
dehydrofluorination of a 1,1-difluoroethane (i.e.,
CHF.sub.2CH.sub.3 or HFC-152a). A mixture comprising vinyl fluoride
and unconverted HFC-152a may be obtained in the vapor phase by
contacting HFC-152a over the catalysts of this invention optionally
in the presence of a diluent selected from the group consisting of
HF, nitrogen, helium, argon, and carbon dioxide. The
dehydrofluorination is preferably conducted at about 150.degree. C.
to about 400.degree. C., more preferably about 250.degree. C. to
about 350.degree. C. If used, the diluent gas, may be present in a
molar ratio of diluent to haloethane of from about 1:1 to about
5:1. Of note are contact times of from about 10 seconds to about 60
seconds.
Chlorodefluorination
[0081] Included in this invention is a process for decreasing the
fluorine content of a halogenated hydrocarbon compound by reacting
said halogenated hydrocarbon compound with hydrogen chloride (HCl)
in the vapor phase in the presence of a catalyst. The process is
characterized by using as the catalyst a composition comprising
chromium, oxygen, and modifier metals as essential constituent
elements (e.g., a composition comprising chromium, oxygen, modifier
metals, and fluorine as essential constituent elements). Suitable
catalyst compositions include those comprising chromium oxide and
modifier metals and/or those prepared by treating compositions
comprising chromium oxide and modifier metals with a fluorinating
agent. The catalyst composition may optionally contain additional
components such as additives to alter the activity and/or the
selectivity of the catalyst.
[0082] Halogenated hydrocarbon compounds suitable as starting
materials for the chlorodefluorination processes of this invention
may be saturated or unsaturated. Saturated halogenated hydrocarbon
compounds suitable for the chlorodefluorination processes of this
invention include those of the general formula
C.sub.nH.sub.aCl.sub.cF.sub.d, wherein n is an integer from 1 to 6,
a is an integer from 0 to 12, c is an integer from 0 to 13, d is an
integer from 1 to 13, and the sum of a, c and d is equal to 2n+2.
Unsaturated halogenated hydrocarbon compounds suitable for the
chlorodefluorination processes of this invention include those of
the general formula C.sub.pH.sub.eCl.sub.gF.sub.h, wherein p is an
integer from 2 to 6, e is an integer from 0 to 10, g is an integer
from 0 to 12, h is an integer from 1 to 11, and the sum of e, g,
and h is equal to 2p. The fluorine content of saturated compounds
of the formula C.sub.nH.sub.aCl.sub.cF.sub.d and/or unsaturated
compounds of the formula C.sub.pH.sub.eCl.sub.gF.sub.h may be
decreased by reacting said compounds with HCl in the vapor phase in
the presence of catalysts of the present invention. Such a process
is referred to herein as a vapor phase chlorodefluorination
reaction. Chlorodefluorination is disclosed in U.S. Pat. No.
5,345,017 and U.S. Pat. No. 5,763,698 and the teachings of these
two patents are hereby incorporated herein by reference.
[0083] The chlorodefluorination reactions are typically conducted
at temperatures of from about 250.degree. C. to 450.degree. C.,
preferably from about 300.degree. C. to about 400.degree. C. The
contact time in the reactor is typically from about 1 to about 120
seconds. Of note are contact times of from about 5 to about 60
seconds. The reactions are most conveniently carried out at
atmospheric or superatmospheric pressure.
[0084] Chlorodefluorinations involving saturated halogenated
hydrocarbons are of particular note. The molar ratio of HCl to the
saturated halogenated hydrocarbon compound is typically from about
1:1 to about 100:1, preferably from about 3:1 to about 50:1, and
most preferably from about 4:1 to about 30:1. In general, with a
given catalyst composition, the higher the temperature, the longer
the contact time, and the greater the molar ratio of HCl to
saturated halogenated hydrocarbon compound, the greater is the
conversion to compounds having lower fluorine content. The above
variables can be balanced, one against the other, so that the
formation of chlorine-substituted products is maximized.
[0085] The product of chlorodefluorination reactions typically
comprise unreacted HCl, HF, unconverted starting material, and
saturated halogenated hydrocarbon compounds having a lower fluorine
content than the starting material by virtue of the substitution of
one or more fluorine substituents for chlorine.
[0086] Specific examples of vapor phase chlorodefluorination
reactions which may be carried out using the catalysts of this
invention include the conversion of CHF.sub.3 to a mixture of
CHCl.sub.3, CHCl.sub.2F, and CHClF.sub.2, the conversion of
CClF.sub.2CClF.sub.2 to a mixture of CCl.sub.3CCl.sub.3,
CCl.sub.3CCl.sub.2F, CCl.sub.3CClF.sub.2, CCl.sub.2FCCl.sub.2F,
CClF.sub.2CCl.sub.2F, and CCl.sub.3CF.sub.3, the conversion of
CF.sub.3CClF.sub.2 to a mixture of CCl.sub.3CCl.sub.3,
CCl.sub.3CCl.sub.2F, CCl.sub.3CClF.sub.2, CCl.sub.2FCCl.sub.2F,
CClF.sub.2CCl.sub.2F, CCl.sub.3CF.sub.3, CClF.sub.2CClF.sub.2, and
CF.sub.3CCl.sub.2F, the conversion of CF.sub.3CCl.sub.2CF.sub.3 to
a mixture of CF.sub.3CCl.sub.2CClF.sub.2,
CF.sub.3CCl.sub.2CCl.sub.2F, CF.sub.3CCl.sub.2CCl.sub.3, and
CClF.sub.2CCl.sub.2CCl.sub.3, and the conversion of
CF.sub.3CH.sub.2CF.sub.3 to a mixture of CCl.sub.2.dbd.CHCF.sub.3,
and CCl.sub.2.dbd.CClCF.sub.3.
[0087] Of note is a catalytic process for producing a mixture
containing 1,1-dichloro-3,3,3-trifluoro-1-propene (i.e.,
CCl.sub.2.dbd.CHCF.sub.3 or HCFC-1223za) and
1,1,2-trichloro-3,3,3-trifluoro-1-propene (i.e.,
CCl.sub.2.dbd.CClCF.sub.3 or CFC-1213xa) by the
chlorodefluorination of 1,1,1,3,3,3-hexafluoropropane (i.e.,
CF.sub.3CH.sub.2CF.sub.3 or HFC-236fa) by reaction of HFC-236fa
with HCl in the vapor phase in the presence of the catalysts of
this invention. The reaction is preferably conducted from about
275.degree. C. to about 450.degree. C., more preferably about
300.degree. C. to about 400.degree. C. with a molar ratio of HCl to
HFC-236fa of preferably from about 3:1 to about 20:1. Of note are
contacts times of from about 1 second to about 40 seconds. Oxygen
in the form of air or co-fed with an inert diluent such as
nitrogen, helium, or argon may be added along with the reactants or
as a separate catalyst treatment, if desired.
[0088] The reaction products obtained by the processes of this
invention can be separated by conventional techniques, such as with
combinations including, but not limited to, scrubbing, decantation,
or distillation. Some of the products of the various embodiments of
this invention may form one or more azeotropes with each other or
with HF.
[0089] The processes of this invention can be carried out readily
using well known chemical engineering practices.
Utility
[0090] Some of the hydrofluorocarbon reaction products obtained
through use of the catalysts disclosed herein will have desired
properties for direct commercial use and/or serve as useful
starting materials for the manufacture of hydrofluoroolefins. For
example, CH.sub.2F.sub.2 (HFC-32), CHF.sub.2CF.sub.3 (HFC-125),
CHF.sub.2CH.sub.3 (HFC-152a), CH.sub.2FCF.sub.3 (HFC-134a),
CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa), and CF.sub.3CH.sub.2CHF.sub.2
(HFC-245fa) find application as refrigerants, CH.sub.2FCF.sub.3
(HFC-134a) and CF.sub.3CHFCF.sub.3 (HFC-227ea) find application as
propellants, CH.sub.3CHF.sub.2 (HFC-152a) and
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) find application as blowing
agents, and CHF.sub.2CF.sub.3 (HFC-125), CF.sub.3CH.sub.2CF.sub.3
(HFC-236fa), and CF.sub.3CHFCF.sub.3 (HFC-227ea) find application
as fire extinguishants. In addition CF.sub.3CH.sub.2CF.sub.3 can be
used to prepare CF.sub.3CH.dbd.CF.sub.2, CF.sub.3CH.sub.2CHF.sub.2
can be used to prepare CF.sub.3CH.dbd.CHF and CF.sub.3CHFCF.sub.3
can be used to prepare CF.sub.3CF.dbd.CF.sub.2.
[0091] Some reaction products obtained through the use of this
invention are used as chemical intermediates to make useful
products. For example, CCl.sub.3CF.sub.3 (CFC-113a) can be used to
prepare CFC-114a which can then be converted to CH.sub.2FCF.sub.3
(HFC-134a) by hydrodechlorination. Similarly,
CF.sub.3CCl.sub.2CF.sub.3 (CFC-216aa) can be used to prepare
CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa) by hydrodechlorination and
CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215zc) can be used to prepare
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) by hydrogenation.
[0092] Embodiments of this invention include, but are not limited
to:
[0093] Embodiment A1. A catalyst composition, comprising chromium,
oxygen, and at least two modifier metals selected from the group
consisting of gold, silver, and palladium, as essential constituent
elements thereof, wherein the total amount of modifier metals is
from about 0.05 atom % to about 10 atom % based on the total amount
of chromium and modifier metals in the catalyst composition.
[0094] Embodiment A2. The catalyst composition of Embodiment A1
further comprising fluorine as an essential constituent
element.
[0095] Embodiment A3. The catalyst composition of Embodiment A1
comprising gold and silver in a mole ratio of from about 10:1 to
about 1:10.
[0096] Embodiment A4. The catalyst composition of Embodiment A1
comprising gold and palladium in a mole ratio of from about 10:1 to
about 1:10.
[0097] Embodiment A5. The catalyst composition of Embodiment A1
comprising silver and palladium in a mole ratio of from about 10:1
to about 1:10.
[0098] Embodiment A6. The catalyst composition of Embodiment A1,
comprising particles of modifier metals supported on a chromium
oxide support.
[0099] Embodiment A7. A process for changing the fluorine
distribution in a hydrocarbon or halogenated hydrocarbon in the
presence of a catalyst, characterized by using the catalyst
composition of Embodiment A1 as the catalyst.
[0100] Embodiment A8. The process of Embodiment A7 wherein the
fluorine content of a halogenated hydrocarbon compound or an
unsaturated hydrocarbon compound is increased by reacting said
compound with hydrogen fluoride in the vapor phase in the presence
of said catalyst composition.
[0101] Embodiment A9. The process of Embodiment A7 wherein the
fluorine content of a halogenated hydrocarbon compound or a
hydrocarbon compound is increased by reacting said compound with HF
and Cl.sub.2 in the presence of said catalyst composition.
[0102] Embodiment A10. The process of Embodiment A7 wherein the
fluorine distribution in a halogenated hydrocarbon compound is
changed by isomerizing said halogenated hydrocarbon compound in the
presence of said catalyst composition.
[0103] Embodiment A11. The process of Embodiment A7 wherein the
fluorine distribution in a halogenated hydrocarbon compound is
changed by disproportionating said halogenated hydrocarbon compound
in the presence of said catalyst composition.
[0104] Embodiment A12. The process of Embodiment A7 wherein the
fluorine content of a halogenated hydrocarbon compound is decreased
by dehydrofluorinating said halogenated hydrocarbon compound in the
presence of said catalyst composition.
[0105] Embodiment A13. The process of Embodiment A7 wherein the
fluorine content of a halogenated hydrocarbon compound is decreased
by reacting said halogenated hydrocarbon compound with HCl in the
vapor phase the presence of said catalyst composition.
[0106] Embodiment A14. A method for preparing the catalyst
composition of Embodiment A1, comprising (a) co-precipitating a
solid by adding ammonium hydroxide to an aqueous solution of a
soluble modifier metal salts and a soluble chromium salt that
contains at least three moles of nitrate per mole of chromium in
the solution and has a modifier metal content of from about 0.05
atom % to about 10 atom % of the total content of modifier metal
and chromium in the solution, to form an aqueous mixture containing
co-precipitated solid; (b) drying said co-precipitated solid formed
in (a); and (c) calcining said dried solid formed in (b) in an
atmosphere containing at least 10% oxygen by volume.
[0107] Embodiment A15. The method of Embodiment A14 further
comprising treating a calcined solid formed in (c) with a
fluorinating agent to form a catalyst composition comprising
chromium, oxygen, modifier metals, and fluorine as essential
elements.
[0108] Embodiment A16. A method for preparing the catalyst
composition of Embodiment A1, comprising (a) impregnating solid
chromium oxide with a solution of a soluble modifier metal salts;
(b) drying the impregnated chromium oxide prepared in (a); and (c)
calcining the dried solid.
[0109] Embodiment A17. The method of Embodiment A16 further
comprising treating a calcined solid formed in (c) with a
fluorinating agent to form a catalyst composition comprising
chromium, oxygen, modifier metals, and fluorine as essential
elements.
[0110] Embodiment A18. A method for preparing the catalyst
composition of Embodiment A1, comprising mixing multiple
compositions, each comprising chromium, oxygen, and at least one
modifier metal.
[0111] Embodiment A19. The method of Embodiment A18 further
comprising treating the mixture of multiple compositions with a
fluorinating agent to form a catalyst composition comprising
chromium, oxygen, modifier metals, and fluorine as essential
elements.
EXAMPLES
Catalyst Preparations
Preparation Example A1
Preparation of 95 Atom % Chromium/2.5 Atom % Gold/2.5 Atom % Silver
Catalyst (400.degree. C.) by Co-Precipitation
[0112] A two liter plastic beaker equipped with a pH probe and
mechanical stirrer was charged with 800 mL of deionized water,
285.1 g of Cr(NO.sub.3).sub.3[9(H.sub.2O)], 16.1 g of gold solution
(HAuCl.sub.4, 23 weight % Au) and 3.2 g of AgNO.sub.3 with stirring
until dissolution was complete. To the stirred solution was slowly
added a 50/50 mixture of ammonium hydroxide to raise the pH from
1.98 to 8.0. The resulting slurry was stirred at room temperature
overnight. It was then dried at 110.degree. C. to 120.degree. C. in
air for about 48 hours. The resulting solid was spread on a shallow
pan and heated in air at the rate of 5.degree. C./minute to bring
the temperature to 400.degree. C. and maintained at 400.degree. C.
for about 24 hours in air. The calcined solid was pressed into
disks, broken up and sieved to provide a -12 to +20 mesh (1.68 to
0.84 mm) fraction that was used in Examples A1 and A6.
Preparation Example A2
Preparation of 95 Atom % Chromium/2.5 Atom % Gold/2.5 Atom % Silver
Catalyst (900.degree. C.) by Co-Precipitation
[0113] Preparation Example A1 was substantially repeated, except
that the resulting solid was calcined in air at a final temperature
of 900.degree. C. The calcined solid was pressed into disks, broken
up and sieved to provide a to +20 mesh (1.68 to 0.84 mm) fraction
that was used in Examples A2 and A7.
Preparation Example A3
Preparation of 95 Atom % Chromium/2.5 Atom % Gold/2.5 Atom %
Palladium Catalyst (400.degree. C.) by Co-Precipitation
[0114] Preparation Example A1 was substantially repeated, using
285.2 g of Cr(NO.sub.3).sub.3[9(H.sub.2O)], 16.0 g of gold solution
(HAuCl.sub.4, 23 weight % Au) and 151.9 g of an aqueous palladium
solution (1.31% Pd). The resulting solid was calcined in air at a
final temperature of 400.degree. C. The calcined solid was pressed
into disks, broken up and sieved to provide a -12 to +20 mesh (1.68
to 0.84 mm) fraction that was used in Examples A3 and A8.
Preparation Example A4
Preparation of 95 Atom % Chromium/2.5 Atom % Palladium/2.5 Atom %
Silver Catalyst (400.degree. C.) by Co-Precipitation
[0115] Preparation Example A1 was substantially repeated, using
285.2 g of Cr(NO.sub.3).sub.3[9(H.sub.2O)], 3.2 g of AgNO.sub.3 and
117.1 g of an aqueous palladium solution (1.70% Pd). The resulting
solid was calcined in air at a final temperature of 400.degree. C.
The calcined solid was pressed into disks, broken up and sieved to
provide a -12 to +20 mesh (1.68 to 0.84 mm) fraction that was used
in Examples A4 and A9.
Preparation Example A5
Preparation of 95 Atom % Chromium/2.5 Atom % Palladium/2.5 Atom %
Silver Catalyst (900.degree. C.) by Co-Precipitation
[0116] Preparation Example A4 was substantially repeated, using
285.2 g of Cr(NO.sub.3).sub.3[9(H.sub.2O)], 3.2 g of AgNO.sub.3 and
117.1 g of an aqueous palladium solution (1.70% Pd). The resulting
solid was calcined in air at a final temperature of 900.degree. C.
The calcined solid was pressed into disks, broken up and sieved to
provide a -12 to +20 mesh (1.68 to 0.84 mm) fraction that was used
in Examples A5 and A10.
Examples A1-A10
General Procedure for Fluorination and Chlorofluorination
[0117] A weighed quantity of pelletized catalyst was placed in a
5/8 inch (1.58 cm) diameter Inconel.TM. nickel alloy reactor tube
heated in a fluidized sand bath. The tube was heated from
50.degree. C. to 175.degree. C. in a flow of nitrogen (50 cc/min;
8.3(10).sup.-7 m.sup.3/sec) over the course of about one hour. HF
was then admitted to the reactor at a flow rate of 50 cc/min
(8.3(10).sup.-7 m.sup.3/sec). After 0.5 to 2 hours the nitrogen
flow was decreased to 20 cc/min (3.3(10).sup.-7 m.sup.3/sec) and
the HF flow increased to 80 cc/min (1.3(10).sup.-6 m.sup.3/sec);
this flow was maintained for about 1 hour. The reactor temperature
was then gradually increased to 400.degree. C. over 3 to 5 hours.
At the end of this period, the HF flow was stopped and the reactor
cooled to the desired operating temperature under 20 sccm
(3.3(10).sup.-7 m.sup.3/sec) nitrogen flow. CFC-1213xa was fed from
a pump to a vaporizer maintained at about 118.degree. C. For
fluorinations, the CFC-1213xa vapor was combined with the
appropriate molar ratios of HF in a 0.5 inch (1.27 cm) diameter
Monel.TM. nickel alloy tube packed with Monel.TM. turnings. The
mixture of reactants then entered the reactor. For
chlorofluorinations, the CFC-1213xa vapor was combined with the
appropriate molar ratios of HF and chlorine prior to entering the
reactor. The reactions were conducted at a nominal pressure of one
atmosphere. Analytical data for identified compounds is given in
units of GC area %.
General Procedure for Fluorocarbon Product Analysis
[0118] The following general procedure is illustrative of the
method used for analyzing the products of fluorination and
chlorofluorination reactions. Part of the total reactor effluent
was sampled on-line for organic product analysis using a gas
chromatograph equipped a mass selective detector (GC-MS). The gas
chromatography was accomplished with a 20 ft. (6.1 m)
long.times.1/8 in. (0.32 cm) diameter tubing containing Krytox.RTM.
perfluorinated polyether on an inert carbon support. The helium
flow was 30 mL/min (5.0(10).sup.-7 m.sup.3/sec). Gas
chromatographic conditions were 60.degree. C. for an initial hold
period of three minutes followed by temperature programming to
200.degree. C. at a rate of 6.degree. C./minute.
[0119] The bulk of the reactor effluent containing organic products
and also inorganic acids such as HCl and HF was treated with
aqueous caustic prior to disposal.
Legend
TABLE-US-00001 [0120] 214ab is CF.sub.3CCl.sub.2CCl.sub.2F 215aa is
CF.sub.3CCl.sub.2CClF.sub.2 215bb is CCl.sub.2FCClFCF.sub.3 216aa
is CF.sub.3CCl.sub.2CF.sub.3 216ba is CClF.sub.2CClFCF.sub.3 217ba
is CF.sub.3CClFCF.sub.3 225da is CF.sub.3CHClCClF.sub.2 226da is
CF.sub.3CHClCF.sub.3 1213xa is CF.sub.3CCl.dbd.CCl.sub.2 1214 is
C.sub.3Cl.sub.2F.sub.4 1215xc is CF.sub.3CCl.dbd.CF.sub.2
Examples A1-A5
Fluorination of CFC-1213xa
[0121] The fluorination of CFC-1213xa was carried out at various
temperatures using the indicated weights of catalysts prepared
according to Catalyst Preparation Examples A1-A5. The molar ratio
of HF to 1213xa was 20:1 for all Examples and the contact time was
5 seconds. The analytical results are summarized in Table A1. Small
quantities of other compounds, not summarized in Table A1 were also
present.
TABLE-US-00002 TABLE A1 T Cr/M1/M2 Calcin T Wt Ex (.degree. C.)
(atom %) (.degree. C.) (g) 1215xc 226da 216aa 1214xb 225da 1213xa
A1 250 Cr/Au/Ag 400 12.4 6.3 0.2 0.3 9.3 0.9 75.7 275 95/2.5/2.5
27.2 1.3 1.5 11.3 1.5 53.1 300 48.7 2.8 2.8 13.2 1.6 28.4 325 61.3
3.5 3.7 14.7 1.6 14.1 350 70.4 5.1 2.5 14.1 1.5 6.2 375 73.4 5.0
1.0 14.4 1.2 4.8 400 74.0 4.1 0.9 15.3 0.9 4.6 A2 300 Cr/Au/Ag 900
18.5 1.4 ND ND 5.1 ND 93.4 325 95/2.5/2.5 3.1 0.1 ND 7.5 ND 89.2
350 6.5 0.1 ND 10.3 ND 83.1 375 10.2 0.3 ND 11.9 ND 77.5 400 13.7
0.4 ND 11.7 ND 74.0 A3 275 Cr/Au/Pd 400 11.7 3.2 93.4 1.1 0.6 1.0
0.3 300 95/2.5/2.5 0.6 97.6 1.0 0.1 0.1 ND 325 0.7 97.2 0.8 0.2 0.1
0.1 350 1.7 94.5 1.1 0.5 ND 0.1 375 3.4 89.2 2.4 1.0 ND 0.3 A4 275
Cr/Ag/Pd 400 12.7 21.2 0.9 1.3 13.1 1.6 57.6 300 95/2.5/2.5 40.9
1.8 4.4 14.5 1.7 32.1 325 55.8 2.7 8.0 13.8 1.6 15.0 350 62.8 3.5
11.1 13.2 1.4 6.9 375 59.6 4.8 15.9 12.9 1.2 4.2 400 57.5 10.6 12.3
12.4 0.9 3.7 A5 275 Cr/Ag/Pd 900 15.5 4.7 0.1 ND 9.7 ND 85.3 300
95/2.5/2.5 23.3 0.4 0.2 15.3 1.0 59.8 325 43.4 0.9 0.4 17.7 1.2
36.4 350 59.8 1.8 1.3 18.4 1.4 16.9 375 67.5 8.7 2.0 14.2 1.3 5.7
400 64.8 14.1 2.7 11.5 0.7 4.6 Note: ND means less than 0.1; M1, M2
mean modifier metals; Calcin. T means calcination temperature; Wt
(g) means catalyst weight
Examples A6-A10
Chlorofluorination of CFC-1213xa
[0122] The chlorofluorination of CFC-1213xa was carried out at
various temperatures using indicated weights of catalyst prepared
according to Catalyst Preparation Examples A1-A5. The HF/1213xa/Cl2
molar ratio was 20/1/4 for all Examples and the contact time was 5
seconds. The analytical results are summarized in Table A2. Small
quantities of other compounds, not summarized in Table A2, were
also present.
TABLE-US-00003 TABLE A2 Reactor Cr/M1/M2 Calcin T Wt Ex Temp (atom
%) (.degree. C.) (g) 216aa 216ba 1214xb 215aa 215bb 1213xa 214ab A6
280 Cr/Au/Ag 400 12.4 0.1 ND 8.4 2.5 14.6 56.4 16.5 300 95/2.5/2.5
0.1 ND 8.5 2.6 15.3 55.6 16.6 325 0.1 0.1 9.2 3.9 17.7 46.5 21.2
350 0.6 0.4 7.3 12.0 29.9 19.6 28.3 375 2.4 1.7 3.4 30.6 33.2 4.1
22.6 400 5.9 4.4 1.0 48.3 28.4 0.6 9.5 A7 300 Cr/Au/Ag ND ND 8.1
0.8 10.9 72.5 6.9 325 95/2.5/2.5 900 18.5 ND ND 5.6 1.0 6.5 74.6
11.7 350 ND 0.1 6.2 2.0 8.0 67.2 15.2 375 0.1 0.3 7.9 5.0 12.5 53.6
18.2 400 0.3 0.7 8.8 8.5 14.8 45.5 17.4 A8 280 Cr/Au/Pd 400 11.7
2.7 1.1 2.0 31.4 32.1 ND 29.1 300 95/2.5/2.5 4.1 2.6 1.0 44.4 31.7
ND 14.5 325 7.2 8.3 0.3 52.5 27.3 ND 2.3 350 12.6 18.5 0.1 50.2
15.9 ND 0.2 375 20.8 28.2 0.0 43.7 4.3 ND 0.1 400 31.5 30.4 0.0
34.0 0.5 ND 0.1 A9 280 Cr/Ag/Pd 400 12.7 9.7 3.6 4.5 14.6 45.2 0.3
17.0 300 95/2.5/2.5 11.2 3.1 2.8 17.4 44.8 0.3 16.8 325 12.7 3.4
0.8 22.5 43.3 0.2 13.8 350 15.3 5.7 0.6 26.8 41.4 0.1 6.7 375 17.0
7.8 0.4 34.8 33.4 0.1 3.8 400 20.3 13.6 0.2 36.9 25.0 0.0 1.0 A10
280 Cr/Ag/Pd 900 15.5 0.8 0.2 14.7 9.3 42.0 20.7 9.1 300 95/2.5/2/5
1.2 0.2 8.0 11.7 38.7 18.0 19.4 325 2.6 0.4 4.1 19.1 44.3 6.7 20.0
350 6.0 1.3 1.3 25.6 48.3 0.7 14.2 375 9.7 2.3 1.0 27.6 44.7 0.4
11.6 400 15.9 4.0 0.8 29.1 39.0 0.3 7.8 Note: ND means less than
0.1; M1, M2 mean modifier metals; Calcin. T means calcination
temperature; Wt (g) means catalyst weight
[0123] The examples above illustrate use of the catalysts of this
invention to increase the fluorine content of a compound. Using the
catalysts of this invention, the fluorine distribution in a
halogenated hydrocarbon compound may be changed by isomerization or
disproportionation or the fluorine content of a compound may be
decreased by dehydrofluorination or by reaction with hydrogen
chloride in a manner analogous to the teachings of International
Publication No. WO 2004/018093 A2, which is incorporated herein by
reference.
B.
[0124] Invention Category B of this application provides a process
for the preparation of CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and
CF.sub.3CHFCH.sub.2F (HFC-245eb).
[0125] In step (a) of the process of this invention, one or more
halopropene compounds of the formula CX.sub.3CCl.dbd.CClX, wherein
each X is independently selected from the group consisting of F and
Cl, are reacted with chlorine (Cl.sub.2) and hydrogen fluoride (HF)
to produce a product mixture comprising CF.sub.3CCl.sub.2CClF.sub.2
(CFC-215aa) and CF.sub.3CClFCCl.sub.2F (CFC-215bb). Accordingly,
this invention provides a process for the preparation of mixtures
of CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and
CF.sub.3CClFCCl.sub.2F (CFC-215bb) from readily available starting
materials.
[0126] Suitable starting materials for the process of this
invention include E- and Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb),
CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa), CClF.sub.2CCl.dbd.CCl.sub.2
(CFC-1212xa), CCl.sub.2FCCl.dbd.CCl.sub.2 (CFC-1211xa), and
CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene, HCP), or mixtures
thereof.
[0127] Due to their availability, CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa) and CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene,
HCP) are the preferred starting materials for the process of the
invention.
[0128] Preferably, the reaction of HF and Cl.sub.2 with
CX.sub.3CCl.dbd.CClX is carried out in the vapor phase in a heated
tubular reactor. A number of reactor configurations are possible,
including vertical and horizontal orientation of the reactor and
different modes of contacting the halopropene starting material(s)
with HF and chlorine. Preferably the HF and chlorine are
substantially anhydrous.
[0129] In one embodiment of step (a), the halopropene starting
material(s) are fed to the reactor containing the
chlorofluorination catalyst. The halopropene starting material(s)
may be initially vaporized and fed to the reaction zone as
gas(es).
[0130] In another embodiment of step (a), the halopropene starting
material(s) may be contacted with HF in a pre-reactor (i.e. prior
to contacting the chlorofluorination catalysts). The pre-reactor
may be empty (i.e., unpacked), but is preferably filled with a
suitable packing such as Monel.TM. or Hastelloy.TM. nickel alloy
turnings or wool, or other material inert to HCl and HF, that
allows for efficient mixing of CX.sub.3CCl.dbd.CClX and HF
vapor.
[0131] If the halopropene starting material(s) are fed to the
pre-reactor as liquid(s), it is preferable for the pre-reactor to
be oriented vertically with CX.sub.3CCl.dbd.CClX entering the top
of the reactor and pre-heated HF vapor introduced at the bottom of
the reactor.
[0132] Suitable temperatures for the pre-reactor are within the
range of from about 80.degree. C. to about 250.degree. C.,
preferably from about 100.degree. C. to about 200.degree. C. Under
these conditions, for example, hexachloropropene is converted to a
mixture containing predominantly CFC-1213xa. The feed rate of the
starting material is determined by the length and diameter of the
reactor, reactor temperature, and the degree of fluorination
desired in the pre-reactor. Slower feed rates at a given
temperature will increase contact time and tend to increase the
amount of conversion of the starting material and increase the
degree of fluorination of the products.
[0133] The term "degree of fluorination" means the extent to which
fluorine atoms replace chlorine substituents in the
CX.sub.3CCl.dbd.CClX starting materials. For example,
CF.sub.3CCl.dbd.CClF represents a higher degree of fluorination
than CClF.sub.2CCl.dbd.CCl.sub.2 and CF.sub.3CCl.sub.2CF.sub.3
represents a higher degree of fluorination than
CClF.sub.2CCl.sub.2CF.sub.3.
[0134] The molar ratio of HF fed to the pre-reactor, or otherwise
to the reaction zone of step (a), to halopropene starting material
fed in step (a), is typically from about stoichiometric to about
50:1. The stoichiometric ratio depends on the average degree of
fluorination of the halopropene starting material(s) and is
typically based on formation of C.sub.3Cl.sub.3F.sub.5 isomers. For
example, if the halopropene is HCP, the stoichiometric ratio of HF
to HCP is 5:1; if the halopropene is CFC-1213xa, the stoichiometric
ratio of HF to CFC-1213xa is 2:1. Preferably, the molar ratio of HF
to halopropene starting material is from about twice the
stoichiometric ratio (based on formation of C.sub.3Cl.sub.3F.sub.5
isomers) to about 30:1. Higher ratios of HF to halopropene are not
particularly beneficial. Lower ratios result in reduced yields of
C.sub.3Cl.sub.3F.sub.5 isomers.
[0135] If the halopropene starting materials are contacted with HF
in a pre-reactor, the effluent from the pre-reactor is then
contacted with chlorine in the reaction zone of step (a).
[0136] In another embodiment of the invention, the halopropene
starting material(s) may be contacted with Cl.sub.2 and HF in a
pre-reactor (i.e. prior to contacting the chlorofluorination
catalyst). The pre-reactor may be empty (i.e., unpacked) but is
preferably filled with a suitable packing such as Monel.TM. or
Hastelloy.TM. nickel alloy turnings or wool, activated carbon, or
other material inert to HCl, HF, and Cl.sub.2 that allows for
efficient mixing of CX.sub.3CCl.dbd.CClX, HF, and Cl.sub.2.
[0137] Typically, at least a portion of the halopropene starting
material(s) react(s) with Cl.sub.2 and HF in the pre-reactor by
addition of Cl.sub.2 to the olefinic bond to give a saturated
halopropane as well as by substitution of at least a portion of the
Cl substituents in the halopropropane and/or halopropene by F.
Suitable temperatures for the pre-reactor in this embodiment of the
invention are within the range of from about 80.degree. C. to about
250.degree. C., preferably from about 100.degree. C. to about
200.degree. C. Higher temperatures result in greater conversion of
the halopropene(s) entering the reactor to saturated products and
greater degrees of halogenation and fluorination in the pre-reactor
products.
[0138] The term "degree of halogenation" means the extent to which
hydrogen substituents in a halocarbon have been replaced by halogen
and the extent to which carbon-carbon double bonds have been
saturated with halogen. For example, CF.sub.3CCl.sub.2CClF.sub.2
has a higher degree of halogenation than CF.sub.3CCl.dbd.CCl.sub.2.
Also, CF.sub.3CCl.sub.2CClF.sub.2 has a higher degree of
halogenation than CF.sub.3CHClCClF.sub.2.
[0139] The molar ratio of Cl.sub.2 to halopropene starting
material(s) is typically from about 1:1 to about 10:1, and is
preferably from about 1:1 to about 5:1. Feeding Cl.sub.2 at less
than a 1:1 ratio will result in the presence of relatively large
amounts of unsaturated materials and hydrogen-containing side
products in the reactor effluent.
[0140] In a preferred embodiment of step (a), the halopropene
starting materials are vaporized, preferably in the presence of HF,
and contacted with HF and Cl.sub.2 in a pre-reactor and then
contacted with the chlorofluorination catalyst. If the preferred
amounts of HF and Cl.sub.2 are fed to the pre-reactor, additional
HF and Cl.sub.2 are not required in the reaction zone.
[0141] Suitable temperatures in the reaction zone(s) of step (a)
are within the range of from about 200.degree. C. to about
400.degree. C., preferably from about 250.degree. C. to about
350.degree. C., depending on the desired conversion of the starting
material and the activity of the catalyst. Reactor temperatures
greater than about 350.degree. C. may result in products having a
degree of fluorination greater than five. In other words, at higher
temperatures, substantial amounts of chloropropanes containing six
or more fluorine substituents (e.g., CF.sub.3CCl.sub.2CF.sub.3 or
CF.sub.3CClFCClF.sub.2) may be formed. Reactor temperature below
about 240.degree. C. may result in a substantial yield of products
with a degree of fluorination less than five (i.e.,
underfluorinates).
[0142] Suitable reactor pressures for vapor phase embodiments of
this invention may be in the range of from about 1 to about 30
atmospheres. Reactor pressures of about 5 atmospheres to about 20
atmospheres may be advantageously employed to facilitate separation
of HCl from other reaction products.
[0143] The chlorofluorination catalysts used in step (a) of this
invention comprise chromium, oxygen and modifier metals (e.g.,
modifier metal-containing chromium oxide) and contain from about
0.05 atom % to about 10 atom % modifier metals based on the total
amount of modifier metals and chromium in the catalyst composition.
Of note are compositions comprising silver and gold wherein the
mole ratio of silver to gold is from about 10:1 to about 1:10. Also
of note are compositions comprising silver and palladium wherein
the mole ratio of silver to palladium is from about 10:1 to about
1:10. Also of note are compositions comprising palladium and gold
wherein the mole ratio of palladium to gold is from about 10:1 to
about 1:10.
[0144] In one embodiment of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.alpha.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the zero
oxidation state) and metallic silver (i.e., silver in the zero
oxidation state). In another embodiment of this invention, the
catalyst composition comprises alpha-chromium oxide (i.e.,
.alpha.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the zero
oxidation state) and palladium. In another embodiment of this
invention, the catalyst composition comprises alpha-chromium oxide
(i.e., .alpha.-Cr.sub.2O.sub.3) and metallic silver (i.e., silver
in the zero oxidation state) and palladium. In another embodiment
of this invention, the catalyst composition comprises
alpha-chromium oxide (i.e., .alpha.-Cr.sub.2O.sub.3), metallic gold
(i.e., gold in the zero oxidation state), metallic silver (i.e.,
silver in the zero oxidation state), and palladium. Of note are
embodiments wherein at least 50 weight % of the chromium component
is present as alpha-chromium oxide. Also of note are embodiments
wherein the gold component consists essentially of metallic gold
having an average particle size of from about 1 nanometer to about
500 nanometers. In certain embodiments of this invention, particles
of metallic gold and at least one of palladium and metallic silver
are dispersed in a matrix comprising chromium oxide. In certain
embodiments of this invention, particles of metallic silver and
palladium are dispersed in a matrix comprising chromium oxide.
[0145] In certain embodiments of this invention, particles of
metallic gold and at least one of palladium and metallic silver are
supported on a chromium oxide support. In some embodiments,
particles of metallic silver and palladium are supported on a
chromium oxide support.
[0146] The catalyst compositions of this invention may further
comprise fluorine as an essential constituent element.
[0147] The amount of modifier metals relative to the total amount
of chromium and modifier metals in the catalyst compositions used
for the chlorofluorination reaction is preferably from about 0.5
atom % to about 5 atom %.
[0148] The modifier metal-containing chromium oxide catalysts used
in the present invention can be formed into various shapes such as
pellets, granules, and extrudates for use in packing reactors. They
can also be used in powder forms.
[0149] Further information on catalyst compositions comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements useful for this invention (including
embodiments further comprising fluorine) is provided in Invention
Category A above and in U.S. Patent Applications 60/903,218 [FL
1356 US PRV] filed Feb. 23, 2007, and 60/927,846 [FL 1356 US PRV1]
filed May 4, 2007, hereby incorporated herein by reference in their
entirety.
[0150] The catalyst compositions used in step (a) of this invention
may further comprise one or more additives in the form of metal
compounds. Such additives may alter the selectivity and/or activity
of the modifier metal-containing chromium oxide catalyst
compositions or the fluorinated modifier metal-containing chromium
oxide catalyst compositions. Suitable additives can be selected
from the group consisting of the fluorides, oxides, and oxyfluoride
compounds of Mg, Ca, Sc, Y, La, Ti, Zr, W, Mn, Re, Fe, Ru, Co, Rh,
Ir, Ni, Pt, Ce, and Zn.
[0151] The total content of the additive(s) in the catalyst
compositions used in step (a) of the present invention may be from
about 0.05 weight % to about 10 weight % based on the total metal
content of the catalyst compositions. The additives may be
incorporated into the catalyst compositions by standard procedures
such as by impregnation or during co-precipitation of the modifier
metal and chromium salts.
[0152] The catalyst compositions used in step (a) of the present
invention can be treated with a fluorinating agent to form catalyst
compositions comprising chromium, oxygen, modifier metals and
fluorine as essential elements. Typically, prior to use as
catalysts, the catalyst compositions are pre-treated with a
fluorinating agent. Typically this fluorinating agent is HF though
other materials may be used such as sulfur tetrafluoride, carbonyl
fluoride, and fluorinated hydrocarbon compounds such as
trichlorofluoromethane, dichlorodifluoromethane,
chlorodifluoromethane, trifluoromethane, and
1,1,2-trichlorotrifluoroethane. This pretreatment can be
accomplished, for example, by placing the catalyst composition in a
suitable container which can also be the reactor to be used to
perform the process in the present invention, and thereafter,
passing HF over the calcined catalyst composition so as to
partially saturate the catalyst composition with HF. This can be
conveniently carried out by passing HF over the catalyst
composition for a period of time, for example, about 0.1 to about
10 hours at a temperature of, for example, about 200.degree. C. to
about 450.degree. C. Nevertheless, this pre-treatment is not
essential.
[0153] Compounds that are produced in the chlorofluorination
process in step (a) include the halopropanes
CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and CF.sub.3CClFCCl.sub.2F
(CFC-215bb).
[0154] Halopropane by-products that have a higher degree of
fluorination than CFC-215aa and CFC-215bb that may be produced in
step (a) include CF.sub.3CCl.sub.2CF.sub.3 (CFC-216aa),
CF.sub.3CClFCClF.sub.2 (CFC-216ba), CF.sub.3CF.sub.2CCl.sub.2F
(CFC-216cb), CF.sub.3CClFCF.sub.3 (CFC-217ba), and
CF.sub.3CHClCF.sub.3 (HCFC-226da).
[0155] Halopropane by-products that may be formed in step (a) which
have lower degrees of fluorination than CFC-215aa and CFC-215bb
include CF.sub.3CCl.sub.2CCl.sub.2F (HCFC-214ab) and
CF.sub.3CCl.sub.2CCl.sub.3 (HCFC-213ab).
[0156] Halopropene by-products that may be formed in step (a)
include CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc), E- and
Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb), and CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa).
[0157] Prior to step (b), CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa)
and CF.sub.3CClFCCl.sub.2F (CFC-215bb) (and optionally HF) from the
effluent from the reaction zone in step (a), are typically
separated from lower boiling components of the effluent (which
typically comprise HCl, Cl.sub.2, HF, overfluorinated products such
as C.sub.3ClF.sub.7 and C.sub.3Cl.sub.2F.sub.6 isomers) and the
underhalogenated and underfluorinated components of the effluent
(which typically comprise C.sub.3ClF.sub.5 and
C.sub.3Cl.sub.2F.sub.4, CFC-214ab, CFC-1212xb and CFC-1213xa).
Underfluorinated and underhalogenated components (e.g., CFC-214ab,
CFC-1212xb, and CFC-1213xa) may be returned to step (a).
[0158] In one embodiment of the present invention, the
overfluorinated components include CFC-216aa, and CFC-216ba, which
are further reacted with hydrogen (H.sub.2), optionally in the
presence of HF, to produce 1,1,1,3,3,3-hexafluoropropane
(HFC-236fa), and at least one of 1,1,1,2,3,3-hexafluoropropane
(HFC-236ea) and hexafluoropropene as disclosed in U.S. Patent
Application 60/927,847 [FL-1367 US PRV] filed May 4, 2007 and
hereby incorporated herein by reference.
[0159] In another embodiment of the invention, the reactor effluent
from step (a) may be delivered to a first distillation column in
which HCl and any HCl azeotropes are removed from the top of column
while the higher boiling components are removed at the bottom of
the column. The products recovered at the bottom of the first
distillation column are then delivered to a second distillation
column in which HF, Cl.sub.2, CF.sub.3CCl.sub.2CF.sub.3
(CFC-216aa), CF.sub.3CClFCClF.sub.2 (CFC-216ba),
CF.sub.3CF.sub.2CCl.sub.2F (CFC-216cb), CF.sub.3CClFCF.sub.3
(CFC-217ba), and CF.sub.3CHClCF.sub.3 (HCFC-226da) and their HF
azeotropes are recovered at the top of the column and CFC-215aa and
CFC-215bb, and any remaining HF and the higher boiling components
are removed from the bottom of the column. The products recovered
from the bottom of the second distillation column may then be
delivered to a further distillation column to separate the
underfluorinated by-products and intermediates to isolate CFC-215aa
and CFC-215bb.
[0160] Optionally, after distillation and separation of HCl from
the reactor effluent of step (a), the resulting mixture of HF and
halopropanes and halopropenes may be delivered to a decanter
controlled at a suitable temperature to permit separation of a
liquid HF-rich phase and a liquid organic-rich phase. The
organic-rich phase may then be processed to isolate the CFC-215aa
and CFC-215bb. The HF-rich phase may then be recycled to the
reactor of step (a), optionally after removal of any organic
components. The decantation step may be used at other points in the
CFC-215aa/CFC-215bb separation scheme where HF is present.
[0161] In step (b) of the process of this invention,
CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and CF.sub.3CClFCCl.sub.2F
(CFC-215bb) produced in step (a) are reacted with hydrogen
(H.sub.2) in a second reaction zone.
[0162] In one embodiment of step (b), a mixture comprising
CFC-215aa and CFC-215bb is delivered in the vapor phase, along with
hydrogen (H.sub.2), to a reactor containing a hydrogenation
catalyst. Hydrogenation catalysts suitable for use in this
embodiment include catalysts comprising at least one metal selected
from the group consisting of iron, ruthenium, rhodium, iridium,
palladium, and platinum. Said catalytic metal component is
typically supported on a carrier such as carbon or graphite. Of
note are carbon supported catalysts in which the carbon support has
been washed with acid and has an ash content below about 0.1% by
weight. Hydrogenation catalysts supported on low ash carbon are
described in U.S. Pat. No. 5,136,113, the teachings of which are
incorporated herein by reference. Of particular note are catalysts
of palladium supported on carbon. The hydrogenation of CFC-215aa
and CFC-215bb to produce HFC-245fa and HFC-245eb is disclosed in
International Publication No. WO 2005/037743 A1, which is
incorporated herein by reference.
[0163] The supported metal catalysts may be prepared by
conventional methods known in the art such as by impregnation of
the carrier with a soluble salt of the catalytic metal (e.g.,
palladium chloride or rhodium nitrate) as described by Satterfield
on page 95 of Heterogenous Catalysis in Industrial Practice,
2.sup.nd edition (McGraw-Hill, New York, 1991). The concentration
of the catalytic metal(s) on the support is typically in the range
of about 0.1% by weight of the catalyst to about 5% by weight.
[0164] The relative amount of hydrogen contacted with CFC-215aa and
CFC-215bb (i.e., trichloropentafluoropropanes,
C.sub.3Cl.sub.3F.sub.5 isomers) in the presence of a hydrogenation
catalyst is typically from about 0.5 mole of H.sub.2 per mole of
trichloropentafluoropropane isomer to about 10 moles of H.sub.2 per
mole of trichloropentafluoropropane isomer, preferably from about 3
moles of H.sub.2 per mole of trichloropentafluoropropane isomer to
about 8 moles of H.sub.2 per mole of trichloropentafluoropropane
isomer.
[0165] Suitable temperatures for the catalytic hydrogenation are
typically in the range of from about 100.degree. C. to about
350.degree. C., preferably from about 125.degree. C. to about
300.degree. C. Temperatures above about 350.degree. C. tend to
result in defluorination side reactions; temperatures below about
125.degree. C. will result in incomplete substitution of Cl for H
in the C.sub.3Cl.sub.3F.sub.5 starting materials. The reactions are
typically conducted at atmospheric pressure or superatmospheric
pressure.
[0166] The effluent from the step (b) reaction zone typically
includes HCl, unreacted hydrogen, CF.sub.3CH.sub.2CHF.sub.2
(HFC-245fa), CF.sub.3CHFCH.sub.2F (HFC-245eb), lower boiling
by-products (typically including CF.sub.3CH.dbd.CF.sub.2
(HFC-1225zc), E- and Z-CF.sub.3CH.dbd.CHF (HFC-1234ze),
CF.sub.3CF.dbd.CH.sub.2 (HFC-1234yf), CF.sub.3CH.sub.2CF.sub.3
(HFC-236fa), CF.sub.3CHFCH.sub.3 (HFC-254eb), and/or
CF.sub.3CH.sub.2CH.sub.3 (HFC-263fb)) and higher boiling
by-products and intermediates (typically including
CF.sub.3CH.sub.2CH.sub.2Cl (HCFC-253fb), CF.sub.3CHFCH.sub.2Cl
(HCFC-244eb), CF.sub.3CClFCH.sub.2F (HCFC-235bb),
CF.sub.3CHClCHF.sub.2 (HCFC-235da), CF.sub.3CHClCClF.sub.2
(HCFC-225da), and/or CF.sub.3CClFCHClF (HCFC-225ba diasteromers))
as well as any HF carried over from step (a) or step (b).
[0167] In step (c), the desired products are recovered. The
HFC-245fa and HFC-245eb are typically separated from the lower
boiling products and higher boiling products by conventional means
(e.g., distillation). Partially chlorinated by-products such as
HCFC-235da, HCFC-235bb, HCFC-225ba, and HCFC-225da may be recycled
back to step (b).
[0168] In one embodiment of the present invention,
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and CF.sub.3CHFCH.sub.2F
(HFC-245eb) produced in step (b), are dehydrofluorinated to produce
a product comprising CF.sub.3CH.dbd.CHF (HFC-1234ze) and
CF.sub.3CF.dbd.CH.sub.2 (HFC-1234yf) and at least one compound
selected from the group consisting of CF.sub.3CH.dbd.CHF and
CF.sub.3CF.dbd.CH.sub.2 is recovered as disclosed in U.S. Patent
Application 60/927,838 [FL-1366 US PRV] filed May 4, 2007 and
hereby incorporated herein by reference.
[0169] HFC-245fa, HFC-245eb and/or mixtures of them may be used as
refrigerants, foam expansion agents or chemical intermediates. Of
note is a foam expansion agent comprising a mixture of
1,1,1,3,3-pentafluoropropane and 1,1,1,2,3-pentafluoropropane
produced in accordance with this invention.
[0170] Embodiments of this invention include, but are not limited
to:
[0171] Embodiment B1. A process for making
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F, comprising (a)
reacting HF, Cl.sub.2, and at least one halopropene of the formula
CX.sub.3CCl.dbd.CClX, wherein each X is independently selected from
the group consisting of F and Cl, to produce a product comprising
CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F, wherein
said CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F are
produced in the presence of a catalyst composition comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements, wherein the total amount of modifier metals
in said catalyst composition is from about 0.05 atom % to about 10
atom % based on the total amount of chromium and modifier metals in
the catalyst composition; (b) reacting CF.sub.3CCl.sub.2CClF.sub.2
and CF.sub.3CClFCCl.sub.2F produced in (a) with H.sub.2, to produce
a product comprising CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CHFCH.sub.2F; and (c) recovering CF.sub.3CH.sub.2CHF.sub.2
and CF.sub.3CHFCH.sub.2F from the product produced in (b).
[0172] Embodiment B2. The process of Embodiment B1 wherein the
halopropene reactant is contacted with Cl.sub.2 and HF in a
pre-reactor.
[0173] Embodiment B3. The process of Embodiment B1 wherein the
halopropene reactant is contacted with HF in a pre-reactor.
[0174] Embodiment B4. The process of Embodiment B1 wherein the
reaction of (b) is conducted in a reaction zone at a temperature of
from about 100.degree. C. to about 350.degree. C. containing a
hydrogenation catalyst.
[0175] Embodiment B5. The process of Embodiment B1 wherein the
amount of modifier metals relative to the total amount of chromium
and modifier metals in the catalyst composition is from about 0.5
atom % to about 5 atom %.
[0176] Embodiment B6. The process of Embodiment B1 wherein the
catalyst composition further comprises fluorine as an essential
constituent element.
[0177] Embodiment B7. The process of Embodiment B1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and metallic silver.
[0178] Embodiment B8. The process of Embodiment B1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and palladium.
[0179] Embodiment B9. The process of Embodiment B1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic
silver and palladium.
[0180] Embodiment B10. The process of Embodiment B1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold,
metallic silver and palladium.
[0181] Embodiment B11. The process of Embodiment B1 wherein the
catalyst composition comprises silver and gold and the mole ratio
of silver to gold is from about 10:1 to about 1:10.
[0182] Embodiment B12. The process of Embodiment B1 wherein the
catalyst composition comprises silver and palladium and the mole
ratio of silver to palladium is from about 10:1 to about 1:10.
[0183] Embodiment B13. The process of Embodiment B1 wherein the
catalyst composition comprises palladium and gold and the mole
ratio of palladium to gold is from about 10:1 to about 1:10.
Examples
[0184] Reference is made to Examples A6-A10 in Invention Category A
above for the chlorofluorination of CFC-1213xa.
[0185] Examination of the data shown in Table A2 above show that
the amount of CFC-215aa and CFC-215bb can be maximized relative to
CFC-216aa and CFC-216ba by controlling the operational variables by
using the catalysts of this invention. The CFC-215aa and CFC-215bb
produced above may be hydrogenated to produce HFC-245fa and
HFC-245eb, respectively, in a manner analogous to the teachings of
International Publication No. WO 2005/037743 A1. The
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F may be recovered
by procedures known to the art.
C.
[0186] Invention Category C of this application provides a process
for the manufacture of CF.sub.3CH.dbd.CHF (HFC-1234ze) and/or
CF.sub.3CF.dbd.CH.sub.2 (HFC-1234yf). The HFC-1234ze and HFC-1234yf
may be recovered as individual products and/or as one or more
mixtures of the two products. HFC-1234ze may exist as one of two
configurational isomers, E or Z. HFC-1234ze as used herein refers
to the isomers, E-HFC-1234ze or Z-HFC-1234ze, as well as any
combinations or mixtures of such isomers.
[0187] In step (a) of the process of this invention, one or more
halopropene compounds of the formula CX.sub.3CCl.dbd.CClX, wherein
each X is independently selected from the group consisting of F and
Cl, are reacted with chlorine (Cl.sub.2) and hydrogen fluoride (HF)
to produce a product mixture comprising CF.sub.3CCl.sub.2CClF.sub.2
(CFC-215aa) and CF.sub.3CClFCCl.sub.2F (CFC-215bb). Accordingly,
this invention provides a process for the preparation of mixtures
of CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and
CF.sub.3CClFCCl.sub.2F (CFC-215bb) from readily available starting
materials.
[0188] Suitable halopropene starting materials CX.sub.3CCl.dbd.CClX
for the process of this invention include E- and
Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb), CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa), CClF.sub.2CCl.dbd.CCl.sub.2 (CFC-1212xa),
CCl.sub.2FCCl.dbd.CCl.sub.2 (CFC-1211xa), and
CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene, HCP), or mixtures
thereof.
[0189] Due to their availability, CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa) and CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene,
HCP) are the preferred starting materials for the process of the
invention.
[0190] Preferably, the reaction of HF and Cl.sub.2 with
CX.sub.3CCl.dbd.CClX is carried out in the vapor phase in a heated
tubular reactor. A number of reactor configurations are possible,
including vertical and horizontal orientation of the reactor and
different modes of contacting the halopropene starting material(s)
with HF and chlorine. Preferably the HF and chlorine are
substantially anhydrous.
[0191] In one embodiment of step (a), the halopropene starting
material(s), HF and Cl.sub.2 are fed to the reaction zone for
contacting the chlorofluorination catalyst. The halopropene
starting material(s) may be initially vaporized and fed to the
reaction zone as gas(es).
[0192] In another embodiment of step (a), the halopropene starting
material(s) may be contacted with HF in a pre-reactor (i.e. prior
to contacting the chlorofluorination catalysts). The pre-reactor
may be empty (i.e., unpacked), but is preferably filled with a
suitable packing such as Monel.TM. or Hastelloy.TM. nickel alloy
turnings or wool, (or other material inert to HCl and HF), which
allows for efficient mixing of CX.sub.3CCl.dbd.CClX and HF
vapor.
[0193] If the halopropene starting material(s) are fed to the
pre-reactor as liquid(s), it is preferable for the pre-reactor to
be oriented vertically with CX.sub.3CCl.dbd.CClX entering the top
of the reactor and pre-heated HF vapor introduced at the bottom of
the reactor.
[0194] Suitable temperatures for the pre-reactor are within the
range of from about 80.degree. C. to about 250.degree. C.,
preferably from about 100.degree. C. to about 200.degree. C. Under
these conditions, for example, hexachloropropene is converted to a
mixture containing predominantly CFC-1213xa. The feed rate of the
starting material is determined by the length and diameter of the
reactor, reactor temperature, and the degree of fluorination
desired in the pre-reactor. Slower feed rates at a given
temperature will increase contact time and tend to increase the
amount of conversion of the starting material and increase the
degree of fluorination of the products.
[0195] The term "degree of fluorination" means the extent to which
fluorine atoms replace chlorine substituents in the
CX.sub.3CCl.dbd.CClX starting materials. For example,
CF.sub.3CCl.dbd.CClF represents a higher degree of fluorination
than CClF.sub.2CCl.dbd.CCl.sub.2 and CF.sub.3CCl.sub.2CF.sub.3
represents a higher degree of fluorination than
CClF.sub.2CCl.sub.2CF.sub.3.
[0196] The molar ratio of HF fed to the pre-reactor, or otherwise
to the reaction zone of step (a), to halopropene starting material
fed in step (a), is typically from about stoichiometric to about
50:1. The stoichiometric ratio depends on the average degree of
fluorination of the halopropene starting material(s) and is
typically based on formation of C.sub.3Cl.sub.3F.sub.5 isomers. For
example, if the halopropene is HCP, the stoichiometric ratio of HF
to HCP is 5:1; if the halopropene is CFC-1213xa, the stoichiometric
ratio of HF to CFC-1213xa is 2:1. Preferably, the molar ratio of HF
to halopropene starting material is from about twice the
stoichiometric ratio (based on formation of C.sub.3Cl.sub.3F.sub.5
isomers) to about 30:1. Higher ratios of HF to halopropene are not
particularly beneficial. Lower ratios result in reduced yields of
C.sub.3Cl.sub.3F.sub.5 isomers.
[0197] If the halopropene starting materials are contacted with HF
in a pre-reactor, the effluent from the pre-reactor is then
contacted with chlorine in the reaction zone of step (a).
[0198] In another embodiment of step (a), the halopropene starting
material(s) may be contacted with Cl.sub.2 and HF in a pre-reactor
(i.e. prior to contacting the chlorofluorination catalyst). The
pre-reactor may be empty (i.e., unpacked) but is preferably filled
with a suitable packing such as Monel.TM. or Hastelloy.TM. nickel
alloy turnings or wool, activated carbon, or other material inert
to HCl, HF, and Cl.sub.2 that allows for efficient mixing of
CX.sub.3CCl.dbd.CClX, HF, and Cl.sub.2.
[0199] Typically, at least a portion of the halopropene starting
material(s) react(s) with Cl.sub.2 and HF in the pre-reactor by
addition of Cl.sub.2 to the olefinic bond to give a saturated
halopropane as well as by substitution of at least a portion of the
Cl substituents in the halopropropane and/or halopropene by F.
Suitable temperatures for the pre-reactor in this embodiment of the
invention are within the range of from about 80.degree. C. to about
250.degree. C., preferably from about 100.degree. C. to about
200.degree. C. Higher temperatures result in greater conversion of
the halopropene(s) entering the reactor to saturated products and
greater degrees of halogenation and fluorination in the pre-reactor
products.
[0200] The term "degree of halogenation" means the extent to which
hydrogen substituents in a halocarbon have been replaced by halogen
and the extent to which carbon-carbon double bonds have been
saturated with halogen. For example, CF.sub.3CCl.sub.2CClF.sub.2
has a higher degree of halogenation than CF.sub.3CCl.dbd.CCl.sub.2.
Also, CF.sub.3CCl.sub.2CClF.sub.2 has a higher degree of
halogenation than CF.sub.3CHClCClF.sub.2.
[0201] The molar ratio of Cl.sub.2 to halopropene starting
material(s) is typically from about 1:1 to about 10:1, and is
preferably from about 1:1 to about 5:1. Feeding Cl.sub.2 at less
than a 1:1 ratio will result in the presence of relatively large
amounts of unsaturated materials and hydrogen-containing side
products in the reactor effluent.
[0202] In a preferred embodiment of step (a), the halopropene
starting materials are vaporized, preferably in the presence of HF,
and contacted with HF and Cl.sub.2 in a pre-reactor and then
contacted with the chlorofluorination catalyst. If the preferred
amounts of HF and Cl.sub.2 are fed to the pre-reactor, additional
HF and Cl.sub.2 are not required in the reaction zone.
[0203] Suitable temperatures in the reaction zone(s) of step (a)
are within the range of from about 200.degree. C. to about
400.degree. C., preferably from about 250.degree. C. to about
350.degree. C., depending on the desired conversion of the starting
material and the activity of the catalyst. Reactor temperatures
greater than about 350.degree. C. may result in products having a
degree of fluorination greater than five. In other words, at higher
temperatures, substantial amounts of chloropropanes containing six
or more fluorine substituents (e.g., CF.sub.3CCl.sub.2CF.sub.3 or
CF.sub.3CClFCClF.sub.2) may be formed. Reactor temperature below
about 240.degree. C. may result in a substantial yield of products
with a degree of fluorination less than five (i.e.,
underfluorinates).
[0204] Suitable reactor pressures for vapor phase embodiments of
this invention may be in the range of from about 1 to about 30
atmospheres. Reactor pressures of about 5 atmospheres to about 20
atmospheres may be advantageously employed to facilitate separation
of HCl from other reaction products.
[0205] The chlorofluorination catalysts used in step (a) of this
invention comprise chromium, oxygen and modifier metals (e.g.,
modifier metal-containing chromium oxide) and contain from about
0.05 atom % to about 10 atom % modifier metals based on the total
amount of modifier metals and chromium in the catalyst composition.
Of note are compositions comprising silver and gold wherein the
mole ratio of silver to gold is from about 10:1 to about 1:10. Also
of note are compositions comprising silver and palladium wherein
the mole ratio of silver to palladium is from about 10:1 to about
1:10. Also of note are compositions comprising palladium and gold
wherein the mole ratio of palladium to gold is from about 10:1 to
about 1:10.
[0206] In one embodiment of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and metallic silver (i.e., silver in the zero
oxidation state). In another embodiment of this invention, the
catalyst composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and palladium. In another embodiment of this
invention, the catalyst composition comprises alpha-chromium oxide
(i.e., .quadrature.-Cr.sub.2O.sub.3) and metallic silver (i.e.,
silver in the zero oxidation state) and palladium. In another
embodiment of this invention, the catalyst composition comprises
alpha-chromium oxide (i.e., .quadrature.-Cr.sub.2O.sub.3), metallic
gold (i.e., gold in the zero oxidation state), metallic silver
(i.e., silver in the zero oxidation state), and palladium. Of note
are embodiments wherein at least 50 weight % of the chromium
component is present as alpha-chromium oxide. Also of note are
embodiments wherein the gold component consists essentially of
metallic gold having an average particle size of from about 1
nanometer to about 500 nanometers. In certain embodiments of this
invention, particles of metallic gold and at least one of palladium
and metallic silver are dispersed in a matrix comprising chromium
oxide. In certain embodiments of this invention, particles of
metallic silver and palladium are dispersed in a matrix comprising
chromium oxide.
[0207] In certain embodiments of this invention, particles of
metallic gold and at least one of palladium and metallic silver are
supported on a chromium oxide support. In some embodiments,
particles of metallic silver and palladium are supported on a
chromium oxide support.
[0208] The catalyst compositions of this invention may further
comprise fluorine as an essential constituent element.
[0209] The amount of modifier metals relative to the total amount
of chromium and modifier metals in the catalyst compositions used
for the chlorofluorination reaction is preferably from about 0.5
atom % to about 5 atom %.
[0210] Further information on catalyst compositions comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements useful for this invention (including
embodiments further comprising fluorine) is provided in Invention
Category A above and in U.S. Patent Applications 60/903,218 [FL
1356 US PRV] filed Feb. 23, 2007, and 60/927,846 [FL 1356 US PRV1]
filed May 4, 2007, hereby incorporated herein by reference in their
entirety.
[0211] The modifier metal-containing chromium oxide catalysts used
in the present invention can be formed into various shapes such as
pellets, granules, and extrudates for use in packing reactors. They
can also be used in powder forms.
[0212] The catalyst compositions used in step (a) of this invention
may further comprise one or more additives in the form of metal
compounds. Such additives may alter the selectivity and/or activity
of the modifier metal-containing chromium oxide catalyst
compositions or the fluorinated modifier metal-containing chromium
oxide catalyst compositions. Suitable additives can be selected
from the group consisting of the fluorides, oxides, and oxyfluoride
compounds of Mg, Ca, Sc, Y, La, Ti, Zr, W, Mn, Re, Fe, Ru, Co, Rh,
Ir, Ni, Pt, Ce, and Zn.
[0213] The total content of the additive(s) in the catalyst
compositions used in step (a) of the present invention may be from
about 0.05 weight % to about 10 weight % based on the total metal
content of the catalyst compositions. The additives may be
incorporated into the catalyst compositions by standard procedures
such as by impregnation or during co-precipitation of the modifier
metal and chromium salts.
[0214] The catalyst compositions used in step (a) of the present
invention can be treated with a fluorinating agent to form catalyst
compositions comprising chromium, oxygen, modifier metals and
fluorine as essential elements. Typically, prior to use as
catalysts, the catalyst compositions are pre-treated with a
fluorinating agent. Typically this fluorinating agent is HF though
other materials may be used such as sulfur tetrafluoride, carbonyl
fluoride, and fluorinated hydrocarbon compounds such as
trichlorofluoromethane, dichlorodifluoromethane,
chlorodifluoromethane, trifluoromethane, and
1,1,2-trichlorotrifluoroethane. This pretreatment can be
accomplished, for example, by placing the catalyst composition in a
suitable container which can also be the reactor to be used to
perform the process in the present invention, and thereafter,
passing HF over the calcined catalyst composition so as to
partially saturate the catalyst composition with HF. This can be
conveniently carried out by passing HF over the catalyst
composition for a period of time, for example, about 0.1 to about
10 hours at a temperature of, for example, about 200.degree. C. to
about 450.degree. C. Nevertheless, this pre-treatment is not
essential.
[0215] Compounds that are produced by the chlorofluorination
process in step (a) include the halopropanes
CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and CF.sub.3CClFCCl.sub.2F
(CFC-215bb).
[0216] Halopropane by-products that have a higher degree of
fluorination than CFC-215aa and CFC-215bb that may be produced in
step (a) include CF.sub.3CCl.sub.2CF.sub.3 (CFC-216aa),
CF.sub.3CClFCClF.sub.2 (CFC-216ba), CF.sub.3CF.sub.2CCl.sub.2F
(CFC-216cb), CF.sub.3CClFCF.sub.3 (CFC-217ba), and
CF.sub.3CHClCF.sub.3 (HCFC-226da).
[0217] Halopropane by-products that may be formed in step (a) which
have lower degrees of fluorination than CFC-215aa and CFC-215bb
include CF.sub.3CCl.sub.2CCl.sub.2F (HCFC-214ab) and
CF.sub.3CCl.sub.2CCl.sub.3 (HCFC-213ab).
[0218] Halopropene by-products that may be formed in step (a)
include CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc), E- and
Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb), and CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa).
[0219] By proper selection of the operating variables, such as
temperature, pressure, contact time and reactant ratios, conversion
to compounds having a higher degree of fluorination than
trichloropentafluoropropanes can be minimized if needed.
[0220] Prior to step (b), CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa)
and CF.sub.3CClFCCl.sub.2F (CFC-215bb) (and optionally HF) from the
effluent from step (a) are typically separated from lower boiling
components of the effluent (which typically comprise HCl, Cl.sub.2,
HF and overfluorinated products such as C.sub.3ClF.sub.7 and
C.sub.3Cl.sub.2F.sub.6 isomers) and the underfluorinated components
of the effluent (which typically comprise C.sub.3Cl.sub.4F.sub.4
isomers, CFC-213ab and/or underhalogenated components such as
C.sub.3ClF.sub.5 and C.sub.3Cl.sub.2F.sub.4 isomers and
CFC-1213xa). Underfluorinated and underhalogenated components
(e.g., CFC-214ab, CFC-1212xb, and CFC-1213xa) may be returned to
step (a).
[0221] In one embodiment of the present invention, the CFC-216aa,
and CFC-216ba produced in step (a) are further reacted with
hydrogen (H.sub.2), optionally in the presence of HF, to produce
1,1,1,3,3,3-hexafluoropropane (HFC-236fa), and at least one of
1,1,1,2,3,3-hexafluoropropane (HFC-236ea), and hexafluoropropene
(HFP) as disclosed in U.S. Patent Application 60/927,847 [FL 1367
US PRV], filed May 4, 2007 and hereby incorporated herein by
reference.
[0222] In another embodiment of the invention, the reactor effluent
from step (a) may be delivered to a first distillation column in
which HCl and any HCl azeotropes are removed from the top of column
while the higher boiling components are removed at the bottom of
the column. The products recovered at the bottom of the first
distillation column are then delivered to a second distillation
column in which HF, Cl.sub.2, CF.sub.3CCl.sub.2CF.sub.3
(CFC-216aa), CF.sub.3CClFCClF.sub.2 (CFC-216ba),
CF.sub.3CF.sub.2CCl.sub.2F (CFC-216cb), CF.sub.3CClFCF.sub.3
(CFC-217ba), and CF.sub.3CHClCF.sub.3 (HCFC-226da) and their HF
azeotropes are recovered at the top of the column and CFC-215aa and
CFC-215bb, and any remaining HF and the higher boiling components
are removed from the bottom of the column. The products recovered
from the bottom of the second distillation column may then be
delivered to a further distillation column to separate the
underfluorinated by-products and intermediates to isolate CFC-215aa
and CFC-215bb.
[0223] Optionally, after distillation and separation of HCl from
the reactor effluent of step (a), the resulting mixture of HF and
halopropanes and halopropenes may be delivered to a decanter
controlled at a suitable temperature to permit separation of a
liquid HF-rich phase and a liquid organic-rich phase. The
organic-rich phase may then be processed to isolate the CFC-215aa
and CFC-215bb. The HF-rich phase may then be recycled to the
reactor of step (a), optionally after removal of any organic
components. The decantation step may be used at other points in the
CFC-215aa/CFC-215bb separation scheme where HF is present.
[0224] In step (b) of the process of this invention,
CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa) and CF.sub.3CClFCCl.sub.2F
(CFC-215bb) produced in step (a) are reacted with hydrogen
(H.sub.2) in a second reaction zone.
[0225] In one embodiment of step (b), a mixture comprising
CFC-215aa and CFC-215bb is delivered in the vapor phase, along with
hydrogen (H.sub.2), to a reactor containing a hydrogenation
catalyst. Hydrogenation catalysts suitable for use in this
embodiment include catalysts comprising at least one metal selected
from the group consisting of iron, ruthenium, rhodium, iridium,
palladium, and platinum. Said catalytic metal component is
typically supported on a carrier such as carbon or graphite.
[0226] Of note are carbon supported catalysts in which the carbon
support has been washed with acid and has an ash content below
about 0.1% by weight. Hydrogenation catalysts supported on low ash
carbon are described in U.S. Pat. No. 5,136,113, the teachings of
which are incorporated herein by reference.
[0227] Of particular note are catalysts containing palladium
supported on carbon. The hydrogenation of CFC-215aa and CFC-215bb
to produce HFC-245fa and HFC-245eb is disclosed in International
Publication No. WO 2005/037743 A1, which is incorporated herein by
reference.
[0228] The supported metal catalysts may be prepared by
conventional methods known in the art such as by impregnation of
the carrier with a soluble salt of the catalytic metal (e.g.,
palladium chloride or rhodium nitrate) as described by Satterfield
on page 95 of Heterogenous Catalysis in Industrial Practice,
2.sup.nd edition (McGraw-Hill, New York, 1991). The concentration
of the catalytic metal(s) on the support is typically in the range
of about 0.1% by weight of the catalyst to about 5% by weight.
[0229] The relative amount of hydrogen contacted with CFC-215aa and
CFC-215bb (i.e., trichloropentafluoropropanes,
C.sub.3Cl.sub.3F.sub.5 isomers) in the presence of a hydrogenation
catalyst is typically from about 0.5 mole of H.sub.2 per mole of
trichloropentafluoropropane isomer to about 10 moles of H.sub.2 per
mole of trichloropentafluoropropane isomer, preferably from about 3
moles of H.sub.2 per mole of trichloropentafluoropropane isomer to
about 8 moles of H.sub.2 per mole of trichloropentafluoropropane
isomer.
[0230] Suitable temperatures for the catalytic hydrogenation are
typically in the range of from about 100.degree. C. to about
350.degree. C., preferably from about 125.degree. C. to about
300.degree. C. Temperatures above about 350.degree. C. tend to
result in defluorination side reactions; temperatures below about
125.degree. C. will result in incomplete substitution of Cl for H
in the C.sub.3Cl.sub.3F.sub.5 starting materials. The reactions are
typically conducted at atmospheric pressure or superatmospheric
pressure.
[0231] The effluent from the step (b) reaction zone typically
includes HCl, unreacted hydrogen, CF.sub.3CH.sub.2CHF.sub.2
(HFC-245fa), CF.sub.3CHFCH.sub.2F (HFC-245eb), lower boiling
by-products (typically including CF.sub.3CH.dbd.CF.sub.2
(HFC-1225zc), E- and Z-CF.sub.3CH.dbd.CHF (HFC-1234ze),
CF.sub.3CF.dbd.CH.sub.2 (HFC-1234yf), CF.sub.3CH.sub.2CF.sub.3
(HFC-236fa), CF.sub.3CHFCH.sub.3 (HFC-254eb), and/or
CF.sub.3CH.sub.2CH.sub.3 (HFC-263fb)) and higher boiling
by-products and intermediates (typically including
CF.sub.3CH.sub.2CH.sub.2Cl (HCFC-253fb), CF.sub.3CHFCH.sub.2Cl
(HCFC-244eb), CF.sub.3CClFCH.sub.2F (HCFC-235bb),
CF.sub.3CHClCHF.sub.2 (HCFC-235da), CF.sub.3CHClCClF.sub.2
(HCFC-225da), and/or CF.sub.3CClFCHClF (HCFC-225ba diasteromers))
as well as any HF carried over from step (a) or step (b).
[0232] In one embodiment of this invention, HFC-245fa and HFC-245eb
produced in step (b) are recovered as disclosed in U.S. Patent
Application 60/927,848 [FL-1365 US PRV] filed May 4, 2007 and
hereby incorporated herein by reference.
[0233] In step (c) of the process, HFC-245fa and HFC-245eb produced
in step (b) are dehydrofluorinated.
[0234] In one embodiment of step (c), a mixture comprising
HFC-245fa and HFC-245eb, and optionally an inert gas, is delivered
in the vapor phase to a reaction zone containing a
dehydrofluorination catalyst as described in U.S. Pat. No.
6,369,284; the teachings of this disclosure are incorporated herein
by reference. Dehydrofluorination catalysts suitable for use in
this embodiment include (1) at least one compound selected from the
oxides, fluorides and oxyfluorides of magnesium, zinc and mixtures
of magnesium and zinc, (2) lanthanum oxide, (3) fluorided lanthanum
oxide, (4) activated carbon, and (5) three-dimensional matrix
carbonaceous materials.
[0235] The catalytic dehydrofluorination of
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F is suitably
conducted at a temperature in the range of from about 200.degree.
C. to about 500.degree. C., and preferably from about 350.degree.
C. to about 450.degree. C. The contact time is typically from about
1 to about 450 seconds, preferably from about 10 to about 120
seconds.
[0236] The reaction pressure can be subatmospheric, atmospheric or
superatmospheric. Generally, near atmospheric pressures are
preferred. However, the dehydrofluorination of
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F can be
beneficially run under reduced pressure (i.e., pressures less than
one atmosphere).
[0237] The catalytic dehydrofluorination can optionally be carried
out in the presence of an inert gas such as nitrogen, helium or
argon. The addition of an inert gas can be used to increase the
extent of dehydrofluorination. Of note are processes where the mole
ratio of inert gas to CF.sub.3CH.sub.2CHF.sub.2 and/or
CF.sub.3CHFCH.sub.2F is from about 5:1 to 1:1. Nitrogen is the
preferred inert gas.
[0238] The products from the step (c) reaction zone typically
include HF, E- and Z-forms of CF.sub.3CH.dbd.CHF (HFC-1234ze),
CF.sub.3CF.dbd.CH.sub.2 (HFC-1234ye), CF.sub.3CH.sub.2CHF.sub.2,
CF.sub.3CHFCH.sub.2F and small amounts of other products.
Unconverted CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F are
recycled back to the dehydrofluorination reactor to produce
additional quantities of CF.sub.3CH.dbd.CHF and
CF.sub.3CF.dbd.CH.sub.2.
[0239] In another embodiment of step (c), the HFC-245fa and
HFC-245eb are subjected to dehydrofluorination at an elevated
temperature in the absence of a catalyst as disclosed in U.S.
Patent Application Publication No. 2006/0094911 which is
incorporated herein by reference. The reactor can be fabricated
from nickel, iron, titanium, or their alloys, as described in U.S.
Pat. No. 6,540,933; the teachings of this disclosure are
incorporated herein by reference.
[0240] The temperature of the reaction in this embodiment can be
between about 350.degree. C. and about 900.degree. C., and is
preferably at least about 450.degree. C.
[0241] In yet another embodiment of step (c), the HFC-245fa and
HFC-245eb are dehydrofluorinated by reaction with caustic (e.g.,
KOH). The vapor-phase dehydrofluorination reaction of
CF.sub.3CHFCHF.sub.2 with caustic to produce both
CF.sub.3CH.dbd.CF.sub.2 and CF.sub.3CF.dbd.CHF is disclosed by
Sianesi, et. al., Ann. Chim., 55, 850-861 (1965) and the
liquid-phase dehydrofluorination of CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CHFCH.sub.2F in di-n-butyl ether, by reaction with caustic,
to produce CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2 is
disclosed by Knunyants, et. al., Izv. Akad. Nauk. SSSR, 1960, pp.
1412-1418, Chem. Abstracts 55, 349f the teachings of which are
incorporated herein by reference.
[0242] In step (d) of the process of this invention, the
CF.sub.3CH.dbd.CHF, CF.sub.3CF.dbd.CH.sub.2, or both
CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2, produced in (c) are
recovered individually and/or as one or more mixtures of
CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2 by well known
procedures, such as distillation.
[0243] CF.sub.3CH.dbd.CHF, CF.sub.3CF.dbd.CH.sub.2, or mixtures
thereof, may be used as refrigerants, foam expansion agents or
chemical intermediates. Of note is a foam expansion agent
comprising a mixture of CF.sub.3CH.dbd.CHF and
CF.sub.3CF.dbd.CH.sub.2 produced in accordance with this
invention.
[0244] Embodiments of this invention include, but are not limited
to:
[0245] Embodiment C1. A process for the manufacture of at least one
compound selected from the group consisting of
1,3,3,3-tetrafluoropropene and 2,3,3,3-tetrafluoropropene,
comprising (a) reacting hydrogen fluoride, chlorine, and at least
one halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein each X
is independently selected from the group consisting of F and Cl, to
produce a product comprising CF.sub.3CCl.sub.2CClF.sub.2 and
CF.sub.3CClFCCl.sub.2F, wherein said CF.sub.3CCl.sub.2CClF.sub.2
and CF.sub.3CClFCCl.sub.2F are produced in the presence of a
catalyst composition comprising chromium, oxygen, and at least two
modifier metals selected from the group consisting of gold, silver,
and palladium as essential constituent elements, wherein the total
amount of modifier metals in said catalyst composition is from
about 0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition; (b)
reacting CF.sub.3CCl.sub.2CClF.sub.2 and CF.sub.3CClFCCl.sub.2F
produced in (a) with hydrogen to produce a product comprising
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CHFCH.sub.2F; (c)
dehydrofluorinating CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CHFCH.sub.2F produced in (b) to produce a product
comprising CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2; and (d)
recovering at least one compound selected from the group consisting
of CF.sub.3CH.dbd.CHF and CF.sub.3CF.dbd.CH.sub.2 from the product
produced in (c).
[0246] Embodiment C2. The process of Embodiment C1 wherein the
halopropene reactant is contacted with Cl.sub.2 and HF in a
pre-reactor.
[0247] Embodiment C3. The process of Embodiment C1 wherein the
halopropene reactant is contacted with HF in a pre-reactor.
[0248] Embodiment C4. The process of Embodiment C1 wherein the
reaction of (b) is conducted in a reaction zone containing a
hydrogenation catalyst at a temperature of from about 100.degree.
C. to about 350.degree. C.
[0249] Embodiment C5. The process of Embodiment C1 wherein the
reaction of (c) is conducted in the absence of a catalyst at a
temperature of from about 350.degree. C. to about 900.degree.
C.
[0250] Embodiment C6. The process of Embodiment C1 wherein the
reaction of (c) is conducted in a reaction zone containing a
dehydrofluorination catalyst at a temperature of from about
200.degree. C. to about 500.degree. C.
[0251] Embodiment C7. The process of Embodiment C1 wherein the
amount of modifier metals relative to the total amount of chromium
and modifier metals in the catalyst composition is from about 0.5
atom % to about 5 atom %.
[0252] Embodiment C8. The process of Embodiment C1 wherein the
catalyst composition further comprises fluorine as an essential
constituent element.
[0253] Embodiment C9. The process of Embodiment C1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and metallic silver.
[0254] Embodiment C10. The process of Embodiment C1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and palladium.
[0255] Embodiment C11. The process of Embodiment C1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic
silver and palladium.
[0256] Embodiment C12. The process of Embodiment C1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold,
metallic silver and palladium.
[0257] Embodiment C13. The process of Embodiment C1 wherein the
catalyst composition comprises silver and gold and the mole ratio
of silver to gold is from about 10:1 to about 1:10.
[0258] Embodiment C14. The process of Embodiment C1 wherein the
catalyst composition comprises silver and palladium and the mole
ratio of silver to palladium is from about 10:1 to about 1:10.
[0259] Embodiment C15. The process of Embodiment C1 wherein the
catalyst composition comprises palladium and gold and the mole
ratio of palladium to gold is from about 10:1 to about 1:10.
Examples
[0260] Reference is made to Examples A6-A10 in Invention Category A
above for the chlorofluorination of CFC-1213xa.
[0261] Examination of the data shown in Table A2 above show that
the amount of CFC-215aa and CFC-215bb can be maximized relative to
CFC-216aa and CFC-216ba by controlling the operational variables by
using the catalysts of this invention. The CFC-215aa and CFC-215bb
produced above may be hydrogenated to produce HFC-245fa and
HFC-245eb, respectively, in a manner analogous to the teachings of
International Publication No. WO 2005/037743 A1. The HFC-245fa and
HFC-245eb may be dehydrofluorinated to HFC-1234ze and HFC-1234yf,
respectively, in accordance with the teachings described in U.S.
Pat. No. 6,369,284. The HFC-1234ze and HFC-1234yf may be recovered
individually or as mixtures of HFC-1234ze and HFC-1234yf by
procedures known to the art.
D.
[0262] Invention Category D of this application provides a process
for the preparation of CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa) and
CF.sub.3CHFCHF.sub.2 (HFC-236ea). This invention also provides a
process for the preparation of HFC-236fa, HFC-236ea and
CF.sub.3CF.dbd.CF.sub.2 (HFP).
[0263] In step (a) of the process of this invention, one or more
halopropene starting materials CX.sub.3CCl.dbd.CClX, wherein each X
is independently selected from the group consisting of F and Cl,
are reacted with chlorine (Cl.sub.2) and hydrogen fluoride (HF) to
produce a product mixture comprising CF.sub.3CCl.sub.2CF.sub.3
(CFC-216aa) and CF.sub.3CClFCClF.sub.2 (CFC-216ba). Accordingly,
this invention also provides a process for the preparation of
mixtures of CF.sub.3CCl.sub.2CF.sub.3 (CFC-216aa) and
CF.sub.3CClFCClF.sub.2 (CFC-216ba) from readily available starting
materials.
[0264] Suitable starting materials for the process of this
invention include E- and Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb),
CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa), CClF.sub.2CCl.dbd.CCl.sub.2
(CFC-1212xa), CCl.sub.2FCCl.dbd.CCl.sub.2 (CFC-1211xa), and
CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene, HCP), or mixtures
thereof.
[0265] Due to their availability, CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa) and CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene,
HCP) are the preferred halopropene starting materials for the
process of the invention.
[0266] Preferably, the reaction of HF and Cl.sub.2 with the
halopropenes CX.sub.3CCl.dbd.CClX is carried out in the vapor phase
in a heated tubular reactor. A number of reactor configurations are
possible, including vertical and horizontal orientation of the
reactor and different modes of contacting the halopropene starting
material(s) with HF and chlorine. Preferably the HF and chlorine
are substantially anhydrous.
[0267] In one embodiment of step (a), the halopropene starting
material(s) are fed to the reactor containing the
chlorofluorination catalyst. The halopropene starting material(s)
may be initially vaporized and fed to the reaction zone as
gas(es).
[0268] In another embodiment of step (a), the halopropene starting
material(s) may be contacted with HF in a pre-reactor (i.e. prior
to contacting the chlorofluorination catalyst). The pre-reactor may
be empty (i.e., unpacked), but is preferably filled with a suitable
packing such as Monel.TM. or Hastelloy.TM. nickel alloy turnings or
wool, or other material inert to HCl and HF, that allows for
efficient mixing of CX.sub.3CCl.dbd.CClX and HF vapor.
[0269] If the halopropene starting material(s) are fed to the
pre-reactor as liquid(s), it is preferable for the pre-reactor to
be oriented vertically with CX.sub.3CCl.dbd.CClX entering the top
of the reactor and pre-heated HF vapor introduced at the bottom of
the reactor.
[0270] Suitable temperatures for the pre-reactor are within the
range of from about 80.degree. C. to about 250.degree. C.,
preferably from about 100.degree. C. to about 200.degree. C. Under
these conditions, for example, hexachloropropene is converted to a
mixture containing predominantly CFC-1213xa. The feed rate of the
starting material is determined by the length and diameter of the
reactor, reactor temperature, and the degree of fluorination
desired in the pre-reactor. Slower feed rates at a given
temperature will increase contact time and tend to increase the
amount of conversion of the starting material and increase the
degree of fluorination of the products.
[0271] The term "degree of fluorination" means the extent to which
fluorine atoms replace chlorine substituents in the
CX.sub.3CCl.dbd.CClX starting materials. For example,
CF.sub.3CCl.dbd.CClF represents a higher degree of fluorination
than CClF.sub.2CCl.dbd.CCl.sub.2 and CF.sub.3CCl.sub.2CF.sub.3
represents a higher degree of fluorination than
CClF.sub.2CCl.sub.2CF.sub.3.
[0272] The molar ratio of HF fed to the pre-reactor, or otherwise
to the reaction zone of step (a), to halopropene starting material
fed in step (a) is typically from about stoichiometric to about
50:1. The stoichiometric ratio depends on the average degree of
fluorination of the halopropene starting material(s) and is
typically based on formation of C.sub.3Cl.sub.2F.sub.6 isomers. For
example, if the halopropene is HCP, the stoichiometric ratio of HF
to HCP is 6:1; if the halopropene is CFC-1213xa, the stoichiometric
ratio of HF to CFC-1213xa is 3:1. Preferably, the molar ratio of HF
to halopropene starting material is from about twice the
stoichiometric ratio (based on formation of C.sub.3Cl.sub.2F.sub.6
isomers) to about 30:1. Higher ratios of HF to halopropene are not
particularly beneficial. Lower ratios result in reduced yields of
C.sub.3Cl.sub.2F.sub.6 isomers.
[0273] If the halopropene starting materials are contacted with HF
in a pre-reactor, the effluent from the pre-reactor is then
contacted with chlorine in the reaction zone of step (a).
[0274] In another embodiment of the invention, the halopropene
starting material(s) may be contacted with Cl.sub.2 and HF in a
pre-reactor (i.e. prior to contacting the chlorofluorination
catalyst). The pre-reactor may be empty (i.e., unpacked) but is
preferably filled with a suitable packing such as Monel.TM. or
Hastelloy.TM. nickel alloy turnings or wool, activated carbon, or
other material inert to HCl, HF, and Cl.sub.2 that allows for
efficient mixing of CX.sub.3CCl.dbd.CClX, HF, and Cl.sub.2.
[0275] Typically, at least a portion of the halopropene starting
material(s) react(s) with Cl.sub.2 and HF in the pre-reactor by
addition of Cl.sub.2 to the olefinic bond to give a saturated
halopropane as well as by substitution of at least a portion of the
Cl substituents in the halopropropane and/or halopropene by F.
Suitable temperatures for the pre-reactor in this embodiment of the
invention are within the range of from about 80.degree. C. to about
250.degree. C., preferably from about 100.degree. C. to about
200.degree. C. Higher temperatures result in greater conversion of
the halopropene(s) entering the reactor to saturated products and
greater degrees of halogenation and fluorination in the pre-reactor
products.
[0276] The term "degree of halogenation" means the extent to which
hydrogen substituents in a halocarbon have been replaced by halogen
and carbon-carbon double bonds have been saturated with halogen.
For example, CF.sub.3CCl.sub.2CClF.sub.2 has a higher degree of
halogenation than CF.sub.3CCl.dbd.CCl.sub.2. Also,
CF.sub.3CCl.sub.2CClF.sub.2 has a higher degree of halogenation
than CF.sub.3CHClCClF.sub.2.
[0277] The molar ratio of Cl.sub.2 to halopropene starting
material(s) is typically from about 1:1 to about 10:1, and is
preferably from about 1:1 to about 5:1. Feeding Cl.sub.2 at less
than a 1:1 ratio will result in the presence of relatively large
amounts of unsaturated materials and hydrogen-containing side
products in the reactor effluent.
[0278] In a preferred embodiment of step (a), the halopropene
starting materials are vaporized, preferably in the presence of HF,
and contacted with HF and Cl.sub.2 in a pre-reactor and then
contacted with the chlorofluorination catalyst. If the preferred
amounts of HF and Cl.sub.2 are fed to the pre-reactor, additional
HF and Cl.sub.2 are not required in the reaction zone.
[0279] Suitable temperatures in the reaction zone(s) of step (a)
are within the range of from about 200.degree. C. to about
400.degree. C., preferably from about 250.degree. C. to about
350.degree. C., depending on the desired conversion of the starting
material and the activity of the catalyst. Reactor temperatures
greater than about 350.degree. C. may result in products having a
degree of fluorination greater than five. In other words, at higher
temperatures, substantial amounts of chloropropanes containing six
or more fluorine substituents (e.g., CF.sub.3CCl.sub.2CF.sub.3 or
CF.sub.3CClFCClF.sub.2) may be formed. Reactor temperatures below
about 240.degree. C. may result in a substantial yield of products
with a degree of fluorination less than five (i.e.,
underfluorinates).
[0280] Suitable reactor pressures for vapor phase embodiments of
this invention may be in the range of from about 1 to about 30
atmospheres. Reactor pressures of about 5 atmospheres to about 20
atmospheres may be advantageously employed to facilitate separation
of HCl from other reaction products.
[0281] The chlorofluorination catalysts used in step (a) of this
invention comprise chromium, oxygen and modifier metals (e.g.,
modifier metal-containing chromium oxide) and contain from about
0.05 atom % to about 10 atom % modifier metals based on the total
amount of modifier metals and chromium in the catalyst composition.
Of note are compositions comprising silver and gold wherein the
mole ratio of silver to gold is from about 10:1 to about 1:10. Also
of note are compositions comprising silver and palladium wherein
the mole ratio of silver to palladium is from about 10:1 to about
1:10. Also of note are compositions comprising palladium and gold
wherein the mole ratio of palladium to gold is from about 10:1 to
about 1:10.
[0282] In one embodiment of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and metallic silver (i.e., silver in the zero
oxidation state). In another embodiment of this invention, the
catalyst composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and palladium. In another embodiment of this
invention, the catalyst composition comprises alpha-chromium oxide
(i.e., .quadrature.-Cr.sub.2O.sub.3) and metallic silver (i.e.,
silver in the zero oxidation state) and palladium. In another
embodiment of this invention, the catalyst composition comprises
alpha-chromium oxide (i.e., .quadrature.-Cr.sub.2O.sub.3), metallic
gold (i.e., gold in the zero oxidation state), metallic silver
(i.e., silver in the zero oxidation state), and palladium. Of note
are embodiments wherein at least 50 weight % of the chromium
component is present as alpha-chromium oxide. Also of note are
embodiments wherein the gold component consists essentially of
metallic gold having an average particle size of from about 1
nanometer to about 500 nanometers. In certain embodiments of this
invention, particles of metallic gold and at least one of palladium
and metallic silver are dispersed in a matrix comprising chromium
oxide. In certain embodiments of this invention, particles of
metallic silver and palladium are dispersed in a matrix comprising
chromium oxide.
[0283] In certain embodiments of this invention, particles of
metallic gold and at least one of palladium and metallic silver are
supported on a chromium oxide support. In some embodiments,
particles of metallic silver and palladium are supported on a
chromium oxide support.
[0284] The catalyst compositions of this invention may further
comprise fluorine as an essential constituent element.
[0285] The amount of modifier metals relative to the total amount
of chromium and modifier metals in the catalyst compositions used
for the chlorofluorination reaction is preferably from about 0.5
atom % to about 5 atom %.
[0286] Further information on catalyst compositions comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements useful for this invention (including
embodiments further comprising fluorine) is provided in Invention
Category A above and in U.S. Patent Applications 60/903,218 [FL
1356 US PRV] filed Feb. 23, 2007, and 60/927,846 [FL 1356 US PRV1]
filed May 4, 2007, hereby incorporated herein by reference in their
entirety.
[0287] The modifier metal-containing chromium oxide catalysts used
in the present invention can be formed into various shapes such as
pellets, granules, and extrudates for use in packing reactors. They
can also be used in powder forms.
[0288] The catalyst compositions used in step (a) of this invention
may further comprise one or more additives in the form of metal
compounds. Such additives may alter the selectivity and/or activity
of the modifier metal-containing chromium oxide catalyst
compositions or the fluorinated modifier metal-containing chromium
oxide catalyst compositions. Suitable additives can be selected
from the group consisting of the fluorides, oxides, and oxyfluoride
compounds of Mg, Ca, Sc, Y, La, Ti, Zr, W, Mn, Re, Fe, Ru, Co, Rh,
Ir, Ni, Pt, Ce, and Zn.
[0289] The total content of the additive(s) in the catalyst
compositions used in step (a) of the present invention may be from
about 0.05 weight % to about 10 weight % based on the total metal
content of the catalyst compositions. The additives may be
incorporated into the catalyst compositions by standard procedures
such as by impregnation or during co-precipitation of the modifier
metal and chromium salts.
[0290] The catalyst compositions used in step (a) of the present
invention can be treated with a fluorinating agent to form catalyst
compositions comprising chromium, oxygen, modifier metals and
fluorine as essential elements. Typically, prior to use as
catalysts, the catalyst compositions are pre-treated with a
fluorinating agent. Typically this fluorinating agent is HF though
other materials may be used such as sulfur tetrafluoride, carbonyl
fluoride, and fluorinated hydrocarbon compounds such as
trichlorofluoromethane, dichlorodifluoromethane,
chlorodifluoromethane, trifluoromethane, and
1,1,2-trichlorotrifluoroethane. This pretreatment can be
accomplished, for example, by placing the catalyst composition in a
suitable container which can also be the reactor to be used to
perform the process in the present invention, and thereafter,
passing HF over the calcined catalyst composition so as to
partially saturate the catalyst composition with HF. This can be
conveniently carried out by passing HF over the catalyst
composition for a period of time, for example, about 0.1 to about
10 hours at a temperature of, for example, about 200.degree. C. to
about 450.degree. C. Nevertheless, this pre-treatment is not
essential.
[0291] Compounds that are produced in the chlorofluorination
process step (a) include the halopropanes CF.sub.3CCl.sub.2CF.sub.3
(CFC-216aa) and CF.sub.3CClFCClF.sub.2 (CFC-216ba).
[0292] Halopropane by-products that have a higher degree of
fluorination than CFC-216aa and CFC-216ba that may be produced in
step (a) include CF.sub.3CClFCF.sub.3 (CFC-217ba) and
CF.sub.3CF.sub.2CF.sub.3 (FC-218).
[0293] Halopropane and halopropene by-products that may be formed
in step (a) which have lower degrees of fluorination and/or
halogenation than CFC-216aa and CFC-216ba include
CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa), CF.sub.3CClFCCl.sub.2F
(CFC-215bb), CF.sub.3CCl.sub.2CCl.sub.2F (CFC-214ab), and
CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc).
[0294] Prior to step (b), the CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2, (and optionally HF) in the effluent from
the reaction zone in step (a), are typically separated from the low
boiling components of the effluent (which typically comprise HCl,
Cl.sub.2, HF, and overfluorinated products such as
CF.sub.3CClFCF.sub.3) and the underfluorinated components (which
typically comprise C.sub.3Cl.sub.3F.sub.5 (e.g., CFC-215aa and
CFC-215bb) isomers, C.sub.3Cl.sub.4F.sub.4 isomers, and/or
underhalogenated components such as C.sub.3Cl.sub.2F.sub.4 isomers
and CF.sub.3CCl.dbd.CCl.sub.2). The higher boiling components may
be returned to step (a).
[0295] In one embodiment of this invention, the underfluorinated
components CFC-215aa and CFC-215bb are converted to
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and CF.sub.3CHFCH.sub.2F
(HFC-245eb) as disclosed in U.S. Patent Application 60/927,848
[FL-1365 US PRV] filed May 4, 2007 and hereby incorporated herein
by reference.
[0296] In another embodiment of this invention, the reactor
effluent from step (a) is delivered to a first distillation column
in which HCl and any HCl azeotropes are removed from the top of the
column while the higher boiling components are removed from the
bottom of the column. The products recovered from the bottom of the
first distillation column are then delivered to a second
distillation column in which HF, Cl.sub.2, and any CFC-217ba are
recovered at the top of the second distillation column and
remaining HF and organic products, comprising
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2, are recovered
at the bottom of the second distillation column. The products
recovered from the bottom of the second distillation column may be
delivered to further distillation columns or may be delivered to a
decanter controlled at a suitable temperature to permit separation
of an organic-rich phase and an HF-rich phase. The HF-rich phase
may be distilled to recover HF that is then recycled to step (a).
The organic-rich phase may then be delivered to step (b).
[0297] In step (b) of the process of this invention,
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2 are contacted
with hydrogen (H.sub.2), optionally in the presence of HF, in a
second reaction zone. The CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 may be fed to the reaction zone at least in
part as their azeotropes with HF.
[0298] In one embodiment of step (b), a mixture comprising
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2, and
optionally containing HF, is delivered in the vapor phase, along
with hydrogen, to a reactor fabricated from nickel, iron, titanium,
or their alloys, as described in U.S. Pat. No. 6,540,933; the
teachings of this disclosure are incorporated herein by
reference.
[0299] The temperature of the reaction in this embodiment of step
(b) can be between about 350.degree. C. to about 800.degree. C.,
and is preferably at least about 450.degree. C. Of note are
processes wherein the reaction of (b) is conducted in a reaction
zone at a temperature of from about 350.degree. C. to about
600.degree. C. which is unpacked or packed with a nickel alloy.
[0300] The molar ratio of hydrogen to the CFC-216aa/CFC-216ba
mixture fed to the reaction zone should be in the range of about
0.1 mole H.sub.2 per mole of CFC-216 isomer to about 60 moles of
H.sub.2 per mole of CFC-216 isomer, more preferably from about 0.4
to 10 moles of H.sub.2 per mole of CFC-216 isomer.
[0301] Alternatively, the contacting of hydrogen with the mixture
of CFC-216aa and CFC-216ba, and optionally HF, is carried out in
the presence of a hydrogenation catalyst. In this embodiment of
step (b), said mixture is delivered in the vapor phase, along with
hydrogen, to the reaction zone containing a hydrogenation catalyst
according to the teachings disclosed in U.S. Patent Application No.
60/706,161 filed on Aug. 5, 2005 and incorporated herein by
reference. Hydrogenation catalysts suitable for use in this
embodiment include catalysts comprising at least one metal selected
from the group consisting of iron, ruthenium, rhodium, iridium,
palladium, and platinum. Said catalytic metal component is
typically supported on a carrier such as carbon or graphite or a
metal oxide, fluorinated metal oxide, or metal fluoride where the
carrier metal is selected from the group consisting of magnesium,
aluminum, titanium, vanadium, chromium, iron, and lanthanum.
Preferred catalysts for the hydrogenolysis include palladium
supported on fluorided alumina or carbon. The hydrogenolysis of
saturated acyclic halofluorocarbons containing 3 or 4 carbon atoms
using palladium supported on carbon is disclosed in U.S. Pat. No.
5,523,501, the teachings of which are incorporated herein by
reference.
[0302] The supported metal catalysts may be prepared by
conventional methods known in the art such as by impregnation of
the carrier with a soluble salt of the catalytic metal (e.g.,
palladium chloride or rhodium nitrate) as described by Satterfield
on page 95 of Heterogenous Catalysis in Industrial Practice,
2.sup.nd edition (McGraw-Hill, New York, 1991). The concentration
of the catalytic metal(s) on the support is typically in the range
of about 0.1% by weight of the catalyst to about 5% by weight.
[0303] Suitable temperatures for the reaction zone containing said
hydrogenation catalyst are in the range of from about 100.degree.
C. to about 350.degree. C., preferably from about 125.degree. C. to
about 300.degree. C. Higher temperatures typically result in
greater conversion of CFC-216aa and CFC-216ba with fewer partially
chlorinated intermediates such as C.sub.3HClF.sub.6 isomers.
[0304] The amount of hydrogen (H.sub.2) fed to the reaction zone
containing said hydrogenation catalyst is typically from about 1
mole of H.sub.2 per mole of dichlorohexafluoropropane to about 20
moles of H.sub.2 per mole of dichlorohexafluoropropane, preferably
from about 2 moles of H.sub.2 per mole of dichlorohexafluoropropane
to about 10 moles of H.sub.2 per mole of
dichlorohexafluoropropane.
[0305] The pressure used in the step (b) reaction zone is not
critical and may be in the range of from about 1 to 30 atmospheres.
A pressure of about 20 atmospheres may be advantageously employed
to facilitate separation of HCl from other reaction products.
[0306] The effluent from the step (b) reaction zone typically
includes HCl, unreacted hydrogen, CF.sub.3CF.dbd.CF.sub.2 (HFP),
CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa) and CF.sub.3CHFCHF.sub.2
(HFC-236ea), as well as any HF carried over from step (a) or step
(b). In addition, small amounts of CF.sub.3CF.sub.2CH.sub.2F
(HFC-236cb), CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc), and partially
chlorinated by-products such as C.sub.3HClF.sub.6 isomers including
CF.sub.3CHClCF.sub.3 (HCFC-226da), CF.sub.3CClFCHF.sub.2
(HCFC-226ba), CF.sub.3CHFCClF.sub.2 (HCFC-226ea), may be
formed.
[0307] In step (c), the desired products are recovered. The reactor
effluent from step (b) may be delivered to a separation unit to
recover CF.sub.3CH.sub.2CF.sub.3 and at least one of
CF.sub.3CHFCHF.sub.2 and CF.sub.3CF.dbd.CF.sub.2. Typically,
CF.sub.3CF.dbd.CF.sub.2, if present, is recovered separately from
CF.sub.3CH.sub.2CF.sub.3 and any CF.sub.3CHFCHF.sub.2. Typically,
CF.sub.3CHFCHF.sub.2, if present, is recovered as a mixture with
CF.sub.3CH.sub.2CF.sub.3. Separation can be accomplished by
well-known procedures such as by distillation.
[0308] In one embodiment of this invention,
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 from step (b) are
dehydrofluorinated to produce CF.sub.3CH.dbd.CF.sub.2 and
CF.sub.3CF.dbd.CHF as disclosed in U.S. Patent Application
60/927,839 [FL-1364 US PRV] filed May 4, 2007 and hereby
incorporated herein by reference.
[0309] The partially chlorinated by-products, including any
unconverted CFC-216ba and CFC-216aa, may be recovered and returned
to step (a) or returned to the hydrogenation reactor in step
(b).
[0310] Embodiments of this invention include, but are not limited
to:
[0311] Embodiment D1. A process for the manufacture of
1,1,1,3,3,3-hexafluoropropane and at least one compound selected
from the group consisting of 1,1,1,2,3,3-hexafluoropropane and
hexafluoropropene, comprising (a) reacting HF, C12, and at least
one halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein each X
is independently selected from the group consisting of F and Cl, to
produce a product comprising CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2, wherein said CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 are produced in the presence of a catalyst
composition comprising chromium, oxygen, and at least two modifier
metals selected from the group consisting of gold, silver, and
palladium as essential constituent elements, wherein the total
amount of modifier metals in said catalyst composition is from
about 0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition; (b)
reacting CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2
produced in (a) with hydrogen, optionally in the presence of HF, to
produce a product comprising CF.sub.3CH.sub.2CF.sub.3 and at least
one compound selected from the group consisting of
CHF.sub.2CHFCF.sub.3, CF.sub.3CF.dbd.CF.sub.2 and
CF.sub.3CFHCF.sub.3; and (c) recovering from the product produced
in (b), CF.sub.3CH.sub.2CF.sub.3 and at least one compound selected
from the group consisting of CHF.sub.2CHFCF.sub.3,
CF.sub.3CF.dbd.CF.sub.2 and CF.sub.3CFHCF.sub.3.
[0312] Embodiment D2. The process of Embodiment D1 wherein the
halopropene reactant is contacted with Cl.sub.2 and HF in a
pre-reactor.
[0313] Embodiment D3. The process of Embodiment D1 wherein the
halopropene reactant is contacted with HF in a pre-reactor.
[0314] Embodiment D4. The process of Embodiment D1 wherein the
reaction of (b) is conducted in a reaction zone at a temperature of
from about 350.degree. C. to about 800.degree. C. which is unpacked
or packed with a nickel alloy.
[0315] Embodiment D5. The process of Embodiment D1 wherein the
reaction of (b) is conducted in a reaction zone at a temperature of
from about 100.degree. C. to about 350.degree. C. containing a
hydrogenation catalyst.
[0316] Embodiment D6. The process of Embodiment D1 wherein the
amount of modifier metals relative to the total amount of chromium
and modifier metals in the catalyst composition is from about 0.5
atom % to about 5 atom %.
[0317] Embodiment D7. The process of Embodiment D1 wherein the
catalyst composition further comprises fluorine as an essential
constituent element.
[0318] Embodiment D8. The process of Embodiment D1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and metallic silver.
[0319] Embodiment D9. The process of Embodiment D1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and palladium.
[0320] Embodiment D10. The process of Embodiment D1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic
silver and palladium.
[0321] Embodiment D11. The process of Embodiment D1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold,
metallic silver and palladium.
[0322] Embodiment D12. The process of Embodiment D1 wherein the
catalyst composition comprises silver and gold and the mole ratio
of silver to gold is from about 10:1 to about 1:10.
[0323] Embodiment D13. The process of Embodiment D1 wherein the
catalyst composition comprises silver and palladium and the mole
ratio of silver to palladium is from about 10:1 to about 1:10.
[0324] Embodiment D14. The process of Embodiment D1 wherein the
catalyst composition comprises palladium and gold and the mole
ratio of palladium to gold is from about 10:1 to about 1:10.
Examples
[0325] Reference is made to Examples A6-A10 in Invention Category A
above for the chlorofluorination of CFC-1213xa.
[0326] Examination of the data shown in Table A2 above shows that
the fluorine content of the starting CFC-1213xa is increased to
produce CFC-216aa and CFC-216ba as well as other useful products
containing a higher fluorine content than the starting material by
using the catalysts of this invention. The
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2 may be
hydrogenated to produce a mixture of CF.sub.3CH.sub.2CF.sub.3 and
at least one of CHF.sub.2CHFCF.sub.3 and CF.sub.3CF.dbd.CF.sub.2
from which CF.sub.3CH.sub.2CF.sub.3 and at least one compound
selected from the group consisting of CHF.sub.2CHFCF.sub.3,
CF.sub.3CF.dbd.CF.sub.2 and CF.sub.3CFHCF.sub.3 may be recovered
using procedures known to the art.
E.
[0327] Invention Category E of this application provides a process
for the preparation of CF.sub.3CH.dbd.CF.sub.2 (HFC-1225zc) and/or
CF.sub.3CF.dbd.CHF (HFC-1225ye). The HFC-1225zc and HFC-1225ye may
be recovered as individual products and/or as one or more mixtures
of the two products. HFC-1225ye as used herein refers to the
isomers, E-HFC-1225ye (CAS Reg No. [5595-10-8]) or Z-HFC-1225ye
(CAS Reg. No. [5528-43-8]), as well as any combinations or mixtures
of such isomers.
[0328] In step (a) of the process of this invention, one or more
halopropene starting materials CX.sub.3CCl.dbd.CClX, wherein each X
is independently selected from the group consisting of F and Cl,
are reacted with chlorine (Cl.sub.2) and hydrogen fluoride (HF) to
produce a product mixture comprising CF.sub.3CCl.sub.2CF.sub.3
(CFC-216aa) and CF.sub.3CClFCClF.sub.2 (CFC-216ba). Accordingly,
this invention also provides a process for the preparation of
mixtures of CF.sub.3CCl.sub.2CF.sub.3 (CFC-216aa) and
CF.sub.3CClFCClF.sub.2 (CFC-216ba) from readily available starting
materials.
[0329] Suitable starting materials for the process of this
invention include E- and Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb),
CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa), CClF.sub.2CCl.dbd.CCl.sub.2
(CFC-1212xa), CCl.sub.2FCCl.dbd.CCl.sub.2 (CFC-1211xa), and
CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene, HCP), or mixtures
thereof.
[0330] Due to their availability, CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa) and CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene,
HCP) are the preferred halopropene starting materials for the
process of the invention.
[0331] Preferably, the reaction of HF and Cl.sub.2 with
CX.sub.3CCl.dbd.CClX is carried out in the vapor phase in a heated
tubular reactor. A number of reactor configurations are possible,
including vertical and horizontal orientation of the reactor and
different modes of contacting the halopropene starting material(s)
with HF and chlorine. Preferably the HF and chlorine are
substantially anhydrous.
[0332] In one embodiment of step (a), the halopropene starting
material(s) are fed to the reactor containing the
chlorofluorination catalyst. The halopropene starting material(s)
may be initially vaporized and fed to the reaction zone as
gas(es).
[0333] In another embodiment of step (a), the halopropene starting
material(s) may be contacted with HF in a pre-reactor (i.e. prior
to contacting the chlorofluorination catalysts). The pre-reactor
may be empty (i.e., unpacked), but is preferably filled with a
suitable packing such as Monel.TM. or Hastelloy.TM. nickel alloy
turnings or wool, or other material inert to HCl and HF, which
allows for efficient mixing of CX.sub.3CCl.dbd.CClX and HF
vapor.
[0334] If the halopropene starting material(s) are fed to the
pre-reactor as liquid(s), it is preferable for the pre-reactor to
be oriented vertically with CX.sub.3CCl.dbd.CClX entering the top
of the reactor and pre-heated HF vapor introduced at the bottom of
the reactor.
[0335] Suitable temperatures for the pre-reactor are within the
range of from about 80.degree. C. to about 250.degree. C.,
preferably from about 100.degree. C. to about 200.degree. C. Under
these conditions, for example, hexachloropropene is converted to a
mixture containing predominantly CFC-1213xa. The feed rate of the
starting material is determined by the length and diameter of the
reactor, reactor temperature, and the degree of fluorination
desired in the pre-reactor. Slower feed rates at a given
temperature will increase contact time and tend to increase the
amount of conversion of the starting material and increase the
degree of fluorination of the products.
[0336] The term "degree of fluorination" means the extent to which
fluorine atoms replace chlorine substituents in the
CX.sub.3CCl.dbd.CClX starting materials. For example,
CF.sub.3CCl.dbd.CClF represents a higher degree of fluorination
than CClF.sub.2CCl.dbd.CCl.sub.2 and CF.sub.3CCl.sub.2CF.sub.3
represents a higher degree of fluorination than
CClF.sub.2CCl.sub.2CF.sub.3.
[0337] The molar ratio of HF fed to the pre-reactor, or otherwise
to the reaction zone of step (a), to halopropene starting material
fed in step (a) is typically from about stoichiometric to about
50:1. The stoichiometric ratio depends on the average degree of
fluorination of the halopropene starting material(s) and is
typically based on formation of C.sub.3Cl.sub.2F.sub.6 isomers. For
example, if the halopropene is HCP, the stoichiometric ratio of HF
to HCP is 6:1; if the halopropene is CFC-1213xa, the stoichiometric
ratio of HF to CFC-1213xa is 3:1. Preferably, the molar ratio of HF
to halopropene starting material is from about twice the
stoichiometric ratio (based on formation of C.sub.3Cl.sub.2F.sub.6
isomers) to about 30:1. Higher ratios of HF to halopropene are not
particularly beneficial. Lower ratios result in reduced yields of
C.sub.3Cl.sub.2F.sub.6 isomers.
[0338] If the halopropene starting materials are contacted with HF
in a pre-reactor, the effluent from the pre-reactor is then
contacted with chlorine in the reaction zone of step (a).
[0339] In another embodiment of the invention, the halopropene
starting material(s) may be contacted with Cl.sub.2 and HF in a
pre-reactor (i.e. prior to contacting the chlorofluorination
catalyst). The pre-reactor may be empty (i.e., unpacked) but is
preferably filled with a suitable packing such as Monel.TM. or
Hastelloy.TM. nickel alloy turnings or wool, activated carbon, (or
other material inert to HCl, HF, and Cl.sub.2) which allows for
efficient mixing of CX.sub.3CCl.dbd.CClX, HF, and Cl.sub.2.
[0340] Typically, at least a portion of the halopropene starting
material(s) react(s) with Cl.sub.2 and HF in the pre-reactor by
addition of Cl.sub.2 to the olefinic bond to give a saturated
halopropane as well as by substitution of at least a portion of the
Cl substituents in the halopropropane and/or halopropene by F.
Suitable temperatures for the pre-reactor in this embodiment of the
invention are within the range of from about 80.degree. C. to about
250.degree. C., preferably from about 100.degree. C. to about
200.degree. C. Higher temperatures result in greater conversion of
the halopropene(s) entering the reactor to saturated products and
greater degrees of halogenation and fluorination in the pre-reactor
products.
[0341] The term "degree of halogenation" means the extent to which
hydrogen substituents in a halocarbon have been replaced by halogen
and the extent to which carbon-carbon double bonds have been
saturated with halogen. For example, CF.sub.3CCl.sub.2CClF.sub.2
has a higher degree of halogenation than CF.sub.3CCl.dbd.CCl.sub.2.
Also, CF.sub.3CCl.sub.2CClF.sub.2 has a higher degree of
halogenation than CF.sub.3CHClCClF.sub.2.
[0342] The molar ratio of Cl.sub.2 to halopropene starting
material(s) in the pre-reactor is typically from about 1:1 to about
10:1, and is preferably from about 1:1 to about 5:1. Feeding
Cl.sub.2 at less than a 1:1 ratio will result in the presence of
relatively large amounts of unsaturated materials and
hydrogen-containing side products in the reactor effluent.
[0343] In a preferred embodiment of step (a), the halopropene
starting materials are vaporized, preferably in the presence of HF,
and contacted with HF and Cl.sub.2 in a pre-reactor and then
contacted with the chlorofluorination catalyst. If the preferred
amounts of HF and Cl.sub.2 are fed to the pre-reactor, additional
HF and Cl.sub.2 are not required in the reaction zone.
[0344] Suitable temperatures in the reaction zone(s) of step (a)
are within the range of from about 200.degree. C. to about
400.degree. C., preferably from about 250.degree. C. to about
350.degree. C., depending on the desired conversion of the starting
material and the activity of the catalyst. Reactor temperatures
greater than about 350.degree. C. may result in products having a
degree of fluorination greater than five. In other words, at higher
temperatures, substantial amounts of chloropropanes containing six
or more fluorine substituents (e.g., CF.sub.3CCl.sub.2CF.sub.3 or
CF.sub.3CClFCClF.sub.2) may be formed. Reactor temperatures below
about 240.degree. C. may result in a substantial yield of products
with a degree of fluorination less than five (i.e.,
underfluorinates).
[0345] Suitable reactor pressures for vapor phase embodiments of
this invention may be in the range of from about 1 to about 30
atmospheres. Reactor pressures of about 5 atmospheres to about 20
atmospheres may be advantageously employed to facilitate separation
of HCl from other reaction products in step (b) of the process.
[0346] The chlorofluorination catalysts used in step (a) of this
invention comprise chromium, oxygen and modifier metals (e.g.,
modifier metal-containing chromium oxide) and contain from about
0.05 atom % to about 10 atom % modifier metals based on the total
amount of modifier metals and chromium in the catalyst composition.
Of note are compositions comprising silver and gold wherein the
mole ratio of silver to gold is from about 10:1 to about 1:10. Also
of note are compositions comprising silver and palladium wherein
the mole ratio of silver to palladium is from about 10:1 to about
1:10. Also of note are compositions comprising palladium and gold
wherein the mole ratio of palladium to gold is from about 10:1 to
about 1:10.
[0347] In one embodiment of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and metallic silver (i.e., silver in the zero
oxidation state). In another embodiment of this invention, the
catalyst composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and palladium. In another embodiment of this
invention, the catalyst composition comprises alpha-chromium oxide
(i.e., .quadrature.-Cr.sub.2O.sub.3) and metallic silver (i.e.,
silver in the zero oxidation state) and palladium. In another
embodiment of this invention, the catalyst composition comprises
alpha-chromium oxide (i.e., .quadrature.-Cr.sub.2O.sub.3), metallic
gold (i.e., gold in the zero oxidation state), metallic silver
(i.e., silver in the zero oxidation state), and palladium. Of note
are embodiments wherein at least 50 weight % of the chromium
component is present as alpha-chromium oxide. Also of note are
embodiments wherein the gold component consists essentially of
metallic gold having an average particle size of from about 1
nanometer to about 500 nanometers. In certain embodiments of this
invention, particles of metallic gold and at least one of palladium
and metallic silver are dispersed in a matrix comprising chromium
oxide. In certain embodiments of this invention, particles of
metallic silver and palladium are dispersed in a matrix comprising
chromium oxide.
[0348] In certain embodiments of this invention, particles of
metallic gold and at least one of palladium and metallic silver are
supported on a chromium oxide support. In some embodiments,
particles of metallic silver and palladium are supported on a
chromium oxide support.
[0349] The catalyst compositions of this invention may further
comprise fluorine as an essential constituent element.
[0350] The amount of modifier metals relative to the total amount
of chromium and modifier metals in the catalyst compositions used
for the chlorofluorination reaction is preferably from about 0.5
atom % to about 5 atom %.
[0351] Further information on catalyst compositions comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements useful for this invention (including
embodiments further comprising fluorine) is provided in Invention
Category A above and in U.S. Patent Applications 60/903,218 [FL
1356 US PRV] filed Feb. 23, 2007, and 60/927,846 [FL 1356 US PRV1]
filed May 4, 2007, hereby incorporated herein by reference in their
entirety.
[0352] The modifier metal-containing chromium oxide catalysts used
in the present invention can be formed into various shapes such as
pellets, granules, and extrudates for use in packing reactors. They
can also be used in powder forms.
[0353] The catalyst compositions used in step (a) of this invention
may further comprise one or more additives in the form of metal
compounds. Such additives may alter the selectivity and/or activity
of the modifier metal-containing chromium oxide catalyst
compositions or the fluorinated modifier metal-containing chromium
oxide catalyst compositions. Suitable additives can be selected
from the group consisting of the fluorides, oxides, and oxyfluoride
compounds of Mg, Ca, Sc, Y, La, Ti, Zr, W, Mn, Re, Fe, Ru, Co, Rh,
Ir, Ni, Pt, Ce, and Zn.
[0354] The total content of the additive(s) in the catalyst
compositions used in step (a) of the present invention may be from
about 0.05 weight % to about 10 weight % based on the total metal
content of the catalyst compositions. The additives may be
incorporated into the catalyst compositions by standard procedures
such as by impregnation or during co-precipitation of the modifier
metal and chromium salts.
[0355] The catalyst compositions used in step (a) of the present
invention can be treated with a fluorinating agent to form catalyst
compositions comprising chromium, oxygen, modifier metals and
fluorine as essential elements. Typically, prior to use as
catalysts, the catalyst compositions are pre-treated with a
fluorinating agent. Typically this fluorinating agent is HF though
other materials may be used such as sulfur tetrafluoride, carbonyl
fluoride, and fluorinated hydrocarbon compounds such as
trichlorofluoromethane, dichlorodifluoromethane,
chlorodifluoromethane, trifluoromethane, and
1,1,2-trichlorotrifluoroethane. This pretreatment can be
accomplished, for example, by placing the catalyst composition in a
suitable container which can also be the reactor to be used to
perform the process in the present invention, and thereafter,
passing HF over the calcined catalyst composition so as to
partially saturate the catalyst composition with HF. This can be
conveniently carried out by passing HF over the catalyst
composition for a period of time, for example, about 0.1 to about
10 hours at a temperature of, for example, about 200.degree. C. to
about 450.degree. C. Nevertheless, this pre-treatment is not
essential.
[0356] Compounds that are produced in the chlorofluorination
process step (a) include the halopropanes CF.sub.3CCl.sub.2CF.sub.3
(CFC-216aa) and CF.sub.3CClFCClF.sub.2 (CFC-216ba).
[0357] Halopropane by-products that have a higher degree of
fluorination than CFC-216aa and CFC-216ba that may be produced in
step (a) include CF.sub.3CClFCF.sub.3 (CFC-217ba) and
CF.sub.3CF.sub.2CF.sub.3 (FC-218).
[0358] Halopropane and halopropene by-products that may be formed
in step (a) which have lower degrees of fluorination and/or
halogenation than CFC-216aa and CFC-216ba include
CF.sub.3CCl.sub.2CClF.sub.2 (CFC-215aa), CF.sub.3CClFCCl.sub.2F
(CFC-215bb), CF.sub.3CCl.sub.2CCl.sub.2F (CFC-214ab), and
CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc).
[0359] Prior to step (b), the CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2, (and optionally HF) in the effluent from
the reaction zone in step (a), are typically separated from the low
boiling components of the effluent (which typically comprise HCl,
Cl.sub.2, HF, and overfluorinated products such as
CF.sub.3CClFCF.sub.3) and the underfluorinated components (which
typically comprise C.sub.3Cl.sub.3F.sub.5 (e.g., CFC-215aa and
CFC-215bb) isomers, C.sub.3Cl.sub.4F.sub.4 isomers, and/or
underhalogenated components such as C.sub.3Cl.sub.2F.sub.4 isomers
and CF.sub.3CCl.dbd.CCl.sub.2). The higher boiling components may
be returned to step (a).
[0360] In one embodiment of this invention, the underfluorinated
components CFC-215aa and CFC-215bb are converted to
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa) and CF.sub.3CHFCH.sub.2F
(HFC-245eb) as disclosed in U.S. Patent Application 60/927,848
[FL-1365 US PRV] filed May 4, 2007 and hereby incorporated herein
by reference.
[0361] In another embodiment of this invention, the reactor
effluent from step (a) is delivered to a first distillation column
in which HCl and any HCl azeotropes are removed from the top of the
column while the higher boiling components are removed from the
bottom of the column. The products recovered from the bottom of the
first distillation column are then delivered to a second
distillation column in which HF, Cl.sub.2, and any CFC-217ba are
recovered at the top of the second distillation column and
remaining HF and organic products, comprising
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2, are recovered
at the bottom of the second distillation column. The products
recovered from the bottom of the second distillation column may be
delivered to further distillation columns or may be delivered to a
decanter controlled at a suitable temperature to permit separation
of an organic-rich phase and an HF-rich phase. The HF-rich phase
may be distilled to recover HF that is then recycled to step (a).
The organic-rich phase may then be delivered to step (b).
[0362] In step (b) of the process of this invention,
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2 are contacted
with hydrogen (H.sub.2), optionally in the presence of HF, in a
second reaction zone. The CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 may be fed to the reaction zone at least in
part as their azeotropes with HF.
[0363] In one embodiment of step (b), a mixture comprising
CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2, and
optionally containing HF, is delivered in the vapor phase, along
with hydrogen, to a reactor fabricated from nickel, iron, titanium,
or their alloys, as described in U.S. Pat. No. 6,540,933; the
teachings of this disclosure are incorporated herein by
reference.
[0364] The temperature of the reaction in this embodiment of step
(b) can be between about 350.degree. C. to about 800.degree. C.,
and is preferably at least about 450.degree. C. Of note are
processes wherein the reaction of (b) is conducted in a reaction
zone at a temperature of from about 350.degree. C. to about
600.degree. C. which is unpacked or packed with a nickel alloy.
[0365] The molar ratio of hydrogen to the CFC-216aa/CFC-216ba
mixture fed to the reaction zone should be in the range of about
0.1 mole H.sub.2 per mole of CFC-216 isomer to about 60 moles of
H.sub.2 per mole of CFC-216 isomer, more preferably from about 0.4
to 10 moles of H.sub.2 per mole of CFC-216 isomer.
[0366] Alternatively, the contacting of hydrogen with the mixture
of CFC-216aa and CFC-216ba, and optionally HF, is carried out in
the presence of a hydrogenation catalyst. In this embodiment of
step (b), said mixture is delivered in the vapor phase, along with
hydrogen, to the reaction zone containing a hydrogenation catalyst
according to the teachings disclosed in U.S. Patent Application No.
60/706,161 filed on Aug. 5, 2005 and incorporated herein by
reference. Hydrogenation catalysts suitable for use in this
embodiment include catalysts comprising at least one metal selected
from the group consisting of iron, ruthenium, rhodium, iridium,
palladium, and platinum. Said catalytic metal component is
typically supported on a carrier such as carbon or graphite or a
metal oxide, fluorinated metal oxide, or metal fluoride where the
carrier metal is selected from the group consisting of magnesium,
aluminum, titanium, vanadium, chromium, iron, and lanthanum.
Preferred catalysts for the hydrogenolysis include palladium
supported on fluorided alumina or carbon. The hydrogenolysis of
saturated acyclic halofluorocarbons containing 3 or 4 carbon atoms
using palladium supported on carbon is disclosed in U.S. Pat. No.
5,523,501, the teachings of which are incorporated herein by
reference.
[0367] The supported metal catalysts may be prepared by
conventional methods known in the art such as by impregnation of
the carrier with a soluble salt of the catalytic metal (e.g.,
palladium chloride or rhodium nitrate) as described by Satterfield
on page 95 of Heterogenous Catalysis in Industrial Practice,
2.sup.nd edition (McGraw-Hill, New York, 1991). The concentration
of the catalytic metal(s) on the support is typically in the range
of about 0.1% by weight of the catalyst to about 5% by weight.
[0368] Suitable temperatures for the reaction zone containing said
hydrogenation catalyst are in the range of from about 100.degree.
C. to about 350.degree. C., preferably from about 125.degree. C. to
about 300.degree. C. Higher temperatures typically result in
greater conversion of CFC-216aa and CFC-216ba with fewer partially
chlorinated intermediates such as C.sub.3HClF.sub.6 isomers.
[0369] The amount of hydrogen (H.sub.2) fed to the reaction zone
containing said hydrogenation catalyst is typically from about 1
mole of H.sub.2 per mole of dichlorohexafluoropropane to about 20
moles of H.sub.2 per mole of dichlorohexafluoropropane, preferably
from about 2 moles of H.sub.2 per mole of dichlorohexafluoropropane
to about 10 moles of H.sub.2 per mole of
dichlorohexafluoropropane.
[0370] The pressure used in the step (b) reaction zone is not
critical and may be in the range of from about 1 to 30 atmospheres.
A pressure of about 20 atmospheres may be advantageously employed
to facilitate separation of HCl from other reaction products.
[0371] The effluent from the step (b) reaction zone typically
includes HCl, unreacted hydrogen, CF.sub.3CF.dbd.CF.sub.2 (HFP),
CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa) and CF.sub.3CHFCHF.sub.2
(HFC-236ea), as well as any HF carried over from step (a) or step
(b). In addition, small amounts of CF.sub.3CF.sub.2CH.sub.2F
(HFC-236cb), CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc), and partially
chlorinated by-products such as C.sub.3HClF.sub.6 isomers including
CF.sub.3CHClCF.sub.3 (HCFC-226da), CF.sub.3CClFCHF.sub.2
(HCFC-226ba), CF.sub.3CHFCClF.sub.2 (HCFC-226ea), may be
formed.
[0372] In one embodiment of this invention, the reactor effluent
from step (b) may be delivered to a separation unit (e.g.,
distillation) to isolate CF.sub.3CH.sub.2CF.sub.3 and
CF.sub.3CHFCHF.sub.2, typically as a mixture.
CF.sub.3CF.dbd.CF.sub.2 may be recovered from the step (b) effluent
as a separate product.
[0373] In step (c) of the process of this invention,
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 produced in step
(b) are dehydrofluorinated.
[0374] In one embodiment of step (c), a mixture comprising
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2, and optionally
an inert gas, is delivered in the vapor phase to a
dehydrofluorination catalyst as described in U.S. Pat. No.
6,369,284; the teachings of this disclosure are incorporated herein
by reference. Dehydrofluorination catalysts suitable for use in
this embodiment include (1) at least one compound selected from the
oxides, fluorides and oxyfluorides of magnesium, zinc and mixtures
of magnesium and zinc, (2) lanthanum oxide, (3) fluorided lanthanum
oxide, (4) activated carbon, and (5) three-dimensional matrix
carbonaceous materials.
[0375] The catalytic dehydrofluorination of
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 is suitably
conducted at a temperature in the range of from about 200.degree.
C. to about 500.degree. C., and preferably from about 350.degree.
C. to about 450.degree. C. The contact time is typically from about
1 to about 450 seconds, preferably from about 10 to about 120
seconds.
[0376] The reaction pressure can be subatmospheric, atmospheric or
superatmospheric. Generally, near atmospheric pressures are
preferred. However, the dehydrofluorination of
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 can be
beneficially run under reduced pressure (i.e., pressures less than
one atmosphere).
[0377] The catalytic dehydrofluorination can optionally be carried
out in the presence of an inert gas such as nitrogen, helium or
argon. The addition of an inert gas can be used to increase the
extent of dehydrofluorination. Of note are processes wherein the
mole ratio of inert gas to CF.sub.3CH.sub.2CF.sub.3 and/or
CF.sub.3CHFCHF.sub.2 is from about 5:1 to 1:1. Nitrogen is the
preferred inert gas.
[0378] The products from the step (c) reaction zone typically
include HF, E- and Z-forms of CF.sub.3CF.dbd.CHF (HFC-1225ye),
CF.sub.3CH.dbd.CF.sub.2 (HFC-1225zc), CF.sub.3CH.sub.2CF.sub.3,
CF.sub.3CHFCHF.sub.2 and small amounts of other products.
Unconverted CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 are
recycled back to the dehydrofluorination reactor to produce
additional quantities of CF.sub.3CF.dbd.CHF and
CF.sub.3CH.dbd.CF.sub.2.
[0379] In another embodiment of step (c), the
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 are subjected to
dehydrofluorination at an elevated temperature in the absence of a
catalyst by using procedures similar to those disclosed in U.S.
Patent Application Publication No. 2006/0094911 which is
incorporated herein by reference. The reactor can be fabricated
from nickel, iron, titanium, or their alloys, as described in U.S.
Pat. No. 6,540,933; the teachings of this disclosure are
incorporated herein by reference.
[0380] The temperature of the reaction in this embodiment can be
between about 350.degree. C. and about 900.degree. C., and is
preferably at least about 450.degree. C.
[0381] In yet another embodiment of step (c), the
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2 are
dehydrofluorinated by reaction with caustic (e.g. KOH) using
procedures known to the art.
[0382] In step (d) of the process of this invention,
CF.sub.3CH.dbd.CF.sub.2, CF.sub.3CF.dbd.CHF, or both
CF.sub.3CH.dbd.CF.sub.2 and CF.sub.3CF.dbd.CHF produced in (c) are
recovered individually and/or as one or more mixtures of
CF.sub.3CH.dbd.CF.sub.2 and CF.sub.3CF.dbd.CHF by well known
procedures such as distillation.
[0383] Embodiments of this invention include, but are not limited
to:
[0384] Embodiment E1. A process for the manufacture of at least one
compound selected from the group consisting of
1,1,3,3,3-pentafluoropropene and 1,2,3,3,3-pentafluoropropene,
comprising (a) reacting hydrogen fluoride, chlorine, and at least
one halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein each X
is independently selected from the group consisting of F and Cl, to
produce a product comprising CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2, wherein said CF.sub.3CCl.sub.2CF.sub.3 and
CF.sub.3CClFCClF.sub.2 are produced in the presence of a catalyst
composition comprising chromium, oxygen, and at least two modifier
metals selected from the group consisting of gold, silver, and
palladium as essential constituent elements, wherein the total
amount of modifier metals in said catalyst composition is from
about 0.05 atom % to about 10 atom % based on the total amount of
chromium and modifier metals in the catalyst composition; (b)
reacting CF.sub.3CCl.sub.2CF.sub.3 and CF.sub.3CClFCClF.sub.2
produced in (a) with hydrogen, optionally in the presence of
hydrogen fluoride, to produce a product comprising
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CHFCHF.sub.2; (c)
dehydrofluorinating CF.sub.3CH.sub.2CF.sub.3 and
CF.sub.3CHFCHF.sub.2 produced in (b) to produce a product
comprising CF.sub.3CH.dbd.CF.sub.2 and CF.sub.3CF.dbd.CHF; and (d)
recovering at least one compound selected from the group consisting
of CF.sub.3CH.dbd.CF.sub.2 and CF.sub.3CF.dbd.CHF from the product
produced in (c).
[0385] Embodiment E2. The process of Embodiment E1 wherein the
halopropene reactant is contacted with Cl.sub.2 and HF in a
pre-reactor.
[0386] Embodiment E3. The process of Embodiment E1 wherein the
halopropene reactant is contacted with HF in a pre-reactor.
[0387] Embodiment E4. The process of Embodiment E1 wherein the
reaction of (b) is conducted in a reaction zone at a temperature of
from about 350.degree. C. to about 800.degree. C. which is unpacked
or packed with a nickel alloy.
[0388] Embodiment E5. The process of Embodiment E1 wherein the
reaction of (b) is conducted in a reaction zone at a temperature of
from about 100.degree. C. to about 350.degree. C. containing a
hydrogenation catalyst.
[0389] Embodiment E6. The process of Embodiment E1 wherein the
reaction of (c) is conducted in the absence of a catalyst at a
temperature of from about 350.degree. C. to about 900.degree.
C.
[0390] Embodiment E7. The process of Embodiment E1 wherein the
reaction of (c) is conducted in a reaction zone containing a
dehydrofluorination catalyst at a temperature of from about
200.degree. C. to about 500.degree. C.
[0391] Embodiment E8. The process of Embodiment E1 wherein the
amount of modifier metals relative to the total amount of chromium
and modifier metals in the catalyst composition is from about 0.5
atom % to about 5 atom %.
[0392] Embodiment E9. The process of Embodiment E1 wherein the
catalyst composition further comprises fluorine as an essential
constituent element.
[0393] Embodiment E10. The process of Embodiment E1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and metallic silver.
[0394] Embodiment E11. The process of Embodiment E1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and palladium.
[0395] Embodiment E12. The process of Embodiment E1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic
silver and palladium.
[0396] Embodiment E13. The process of Embodiment E1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold,
metallic silver and palladium.
[0397] Embodiment E14. The process of Embodiment E1 wherein the
catalyst composition comprises silver and gold and the mole ratio
of silver to gold is from about 10:1 to about 1:10.
[0398] Embodiment E15. The process of Embodiment E1 wherein the
catalyst composition comprises silver and palladium and the mole
ratio of silver to palladium is from about 10:1 to about 1:10.
[0399] Embodiment E16. The process of Embodiment E1 wherein the
catalyst composition comprises palladium and gold and the mole
ratio of palladium to gold is from about 10:1 to about 1:10.
Examples
[0400] Reference is made to Examples A6-A10 in Invention Category A
above for the chlorofluorination of CFC-1213xa.
[0401] Examination of the data shown in Table A2 above shows that
the amount of CFC-216aa and CFC-216ba can be maximized relative to
CFC-215aa and CFC-215bb by controlling the operational variables
and by using the catalysts of this invention. The CFC-216aa and
CFC-216ba produced above may be hydrogenated to produce HFC-236fa
and HFC-236ea, respectively, in a manner analogous to the teachings
of International Publication No. WO 2005/037743 A1 and U.S. Pat.
No. 5,523,501. The HFC-236fa and HFC-236ea may be
dehydrofluorinated to HFC-1225zc and HFC-1225ye, respectively, in
accordance with the teachings described in U.S. Pat. No. 6,369,284.
The HFC-1225zc and HFC-1225ye may be recovered individually or as
mixtures of HFC-1225zc and HFC-1225ye by procedures known to the
art.
F.
[0402] Invention Category F of this application provides a process
for the preparation of CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa),
CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa), or both
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3. The
HFC-245fa and HFC-236fa may be recovered as individual products
and/or as one or more mixtures of the two products.
[0403] In step (a) of the process of this invention, one or more
halopropene compounds of the formula CX.sub.3CCl.dbd.CClX, wherein
each X is independently selected from the group consisting of F and
Cl, are reacted with hydrogen fluoride (HF) to produce a product
mixture comprising at least one of CF.sub.3CCl.dbd.CF.sub.2
(CFC-1215xc) and CF.sub.3CHClCF.sub.3 (HCFC-226da). Accordingly,
this invention provides a process for the preparation of at least
one of CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 from
readily available starting materials.
[0404] Suitable starting materials for the process of this
invention include E- and Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb),
CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa), CClF.sub.2CCl.dbd.CCl.sub.2
(CFC-1212xa), CCl.sub.2FCCl.dbd.CCl.sub.2 (CFC-1211xa), and
CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene, HCP), or mixtures
thereof.
[0405] Due to their availability, CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa) and CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene,
HCP) are the preferred starting materials for the process of the
invention.
[0406] Preferably, the reaction of HF with CX.sub.3CCl.dbd.CClX is
carried out in the vapor phase in a heated tubular reactor. A
number of reactor configurations are possible, including vertical
and horizontal orientation of the reactor and different modes of
contacting the halopropene starting material(s) with HF. Preferably
the HF is substantially anhydrous.
[0407] In one embodiment of step (a), the halopropene starting
material(s) and HF may be fed to the reactor containing the
fluorination catalyst. The halopropene starting material(s) may be
initially vaporized and fed to the reactor as gas(es).
[0408] In another embodiment of step (a), the halopropene starting
material(s) may be contacted with HF in a pre-reactor (i.e. prior
to contacting the fluorination catalyst). The pre-reactor may be
empty (i.e., unpacked), but is preferably filled with a suitable
packing such as Monel.TM. or Hastelloy.TM. nickel alloy turnings or
wool, or other material inert to HCl and HF, for efficient mixing
of CX.sub.3CCl.dbd.CClX and HF.
[0409] If the halopropene starting material(s) are fed to the
pre-reactor as liquid(s), it is preferable for the pre-reactor to
be oriented vertically with CX.sub.3CCl.dbd.CClX entering the top
of the reactor and pre-heated HF vapor introduced at the bottom of
the reactor.
[0410] Suitable temperatures for the pre-reactor are within the
range of from about 80.degree. C. to about 250.degree. C.,
preferably from about 100.degree. C. to about 200.degree. C. Under
these conditions, for example, hexachloropropene is converted to a
mixture containing predominantly CFC-1213xa. The feed rate of the
starting material is determined by the length and diameter of the
reactor, reactor temperature, and the degree of fluorination
desired in the pre-reactor. Slower feed rates at a given
temperature will increase contact time and tend to increase the
amount of conversion of the starting material and increase the
degree of fluorination of the products.
[0411] The term "degree of fluorination" means the extent to which
fluorine atoms replace chlorine substituents in the
CX.sub.3CCl.dbd.CClX starting materials. For example,
CF.sub.3CCl.dbd.CClF represents a higher degree of fluorination
than CClF.sub.2CCl.dbd.CCl.sub.2 and CF.sub.3CCl.sub.2CF.sub.3
represents a higher degree of fluorination than
CClF.sub.2CCl.sub.2CF.sub.3.
[0412] The molar ratio of HF fed to the pre-reactor, or otherwise
to the reaction zone of step (a), to halopropene starting material
fed in step (a) is typically from about stoichiometric to about
50:1. The stoichiometric ratio depends on the average degree of
fluorination of the halopropene starting material(s) and is
typically based on formation of C.sub.3ClF.sub.5. For example, if
the halopropene is HCP, the stoichiometric ratio of HF to HCP is
5:1; if the halopropene is CFC-1213xa, the stoichiometric ratio of
HF to CFC-1213xa is 2:1. Preferably, the molar ratio of HF to
halopropene starting material is from about twice the
stoichiometric ratio (based on formation of C.sub.3ClF.sub.5) to
about 30:1. Higher ratios of HF to halopropene are not particularly
beneficial. Lower ratios result in reduced yields of CFC-1215xc and
HCFC-226da.
[0413] In a preferred embodiment of step (a) the halopropene
starting materials are vaporized, preferably in the presence of HF,
contacted with HF in a pre-reactor, and then contacted with the
fluorination catalyst. If the preferred amount of HF is fed in the
pre-reactor, additional HF is not required in the reaction zone(s)
of step (a).
[0414] Suitable temperatures in the reaction zone(s) of step (a)
for catalytic fluorination of halopropene starting materials and/or
their products formed in the pre-reactor are within the range of
about 200.degree. C. to about 400.degree. C., preferably from about
240.degree. C. to about 350.degree. C., depending on the desired
conversion of the starting material and the activity of the
catalyst. Higher temperatures typically contribute to reduced
catalyst life. Temperatures below about 240.degree. C. may result
in substantial amounts of products having a degree of fluorination
less than five (i.e., underfluorinates). By adjusting process
conditions such as temperature, contact time, and HF ratios,
greater or lesser amounts of CFC-1215xc relative to HCFC-226da can
be formed.
[0415] Suitable reactor pressures for vapor phase embodiments of
this invention may be in the range of from about 1 to about 30
atmospheres. Reactor pressures of about 5 atmospheres to about 20
atmospheres may be advantageously employed to facilitate separation
of HCl from other reaction products in step (b) of the process.
[0416] The fluorination catalysts used in step (a) of this
invention comprise chromium, oxygen and modifier metals (e.g.,
modifier metal-containing chromium oxide) and contain from about
0.05 atom % to about 10 atom % modifier metals based on the total
amount of modifier metals and chromium in the catalyst composition.
Of note are compositions comprising silver and gold wherein the
mole ratio of silver to gold is from about 10:1 to about 1:10. Also
of note are compositions comprising silver and palladium wherein
the mole ratio of silver to palladium is from about 10:1 to about
1:10. Also of note are compositions comprising palladium and gold
wherein the mole ratio of palladium to gold is from about 10:1 to
about 1:10.
[0417] In one embodiment of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and metallic silver (i.e., silver in the zero
oxidation state). In another embodiment of this invention, the
catalyst composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and palladium. In another embodiment of this
invention, the catalyst composition comprises alpha-chromium oxide
(i.e., .quadrature.-Cr.sub.2O.sub.3) and metallic silver (i.e.,
silver in the zero oxidation state) and palladium. In another
embodiment of this invention, the catalyst composition comprises
alpha-chromium oxide (i.e., .quadrature.-Cr.sub.2O.sub.3), metallic
gold (i.e., gold in the zero oxidation state), metallic silver
(i.e., silver in the zero oxidation state), and palladium. Of note
are embodiments wherein at least 50 weight % of the chromium
component is present as alpha-chromium oxide. Also of note are
embodiments wherein the gold component consists essentially of
metallic gold having an average particle size of from about 1
nanometer to about 500 nanometers. In certain embodiments of this
invention, particles of metallic gold and at least one of palladium
and metallic silver are dispersed in a matrix comprising chromium
oxide. In certain embodiments of this invention, particles of
metallic silver and palladium are dispersed in a matrix comprising
chromium oxide.
[0418] In certain embodiments of this invention, particles of
metallic gold and at least one of palladium and metallic silver are
supported on a chromium oxide support. In some embodiments,
particles of metallic silver and palladium are supported on a
chromium oxide support.
[0419] The catalyst compositions of this invention may further
comprise fluorine as an essential constituent element.
[0420] The amount of modifier metals relative to the total amount
of chromium and modifier metals in the catalyst compositions used
for the fluorination reaction is preferably from about 0.5 atom %
to about 5 atom %.
[0421] Further information on catalyst compositions comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements useful for this invention (including
embodiments further comprising fluorine) is provided in Invention
Category A above and in U.S. Patent Applications 60/903,218 [FL
1356 US PRV] filed Feb. 23, 2007, and 60/927,846 [FL 1356 US PRV1]
filed May 4, 2007, hereby incorporated herein by reference in their
entirety.
[0422] The modifier metal-containing chromium oxide catalysts used
in the present invention can be formed into various shapes such as
pellets, granules, and extrudates for use in packing reactors. They
can also be used in powder forms.
[0423] The catalyst compositions used in step (a) of this invention
may further comprise one or more additives in the form of metal
compounds. Such additives may alter the selectivity and/or activity
of the modifier metal-containing chromium oxide catalyst
compositions or the fluorinated modifier metal-containing chromium
oxide catalyst compositions. Suitable additives can be selected
from the group consisting of the fluorides, oxides, and oxyfluoride
compounds of Mg, Ca, Sc, Y, La, Ti, Zr, W, Mn, Re, Fe, Ru, Co, Rh,
Ir, Ni, Pt, Ce, and Zn.
[0424] The total content of the additive(s) in the catalyst
compositions used in step (a) of the present invention may be from
about 0.05 weight % to about 10 weight % based on the total metal
content of the catalyst compositions. The additives may be
incorporated into the catalyst compositions by standard procedures
such as by impregnation or during co-precipitation of the modifier
metal and chromium salts.
[0425] The catalyst compositions used in step (a) of the present
invention can be treated with a fluorinating agent to form catalyst
compositions comprising chromium, oxygen, modifier metals and
fluorine as essential elements. Typically, prior to use as
catalysts, the catalyst compositions are pre-treated with a
fluorinating agent. Typically this fluorinating agent is HF though
other materials may be used such as sulfur tetrafluoride, carbonyl
fluoride, and fluorinated hydrocarbon compounds such as
trichlorofluoromethane, dichlorodifluoromethane,
chlorodifluoromethane, trifluoromethane, and
1,1,2-trichlorotrifluoroethane. This pretreatment can be
accomplished, for example, by placing the calcined catalyst
composition in a suitable container which can also be the reactor
to be used to perform the process in the present invention, and
thereafter, passing HF over the calcined catalyst composition so as
to partially saturate the catalyst composition with HF. This can be
conveniently carried out by passing HF over the catalyst
composition for a period of time, for example, about 0.1 to about
10 hours at a temperature of, for example, about 200.degree. C. to
about 450.degree. C. Nevertheless, this pre-treatment is not
essential.
[0426] Compounds that are produced in the fluorination process step
(a) include the CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc) and
CF.sub.3CHClCF.sub.3 (HCFC-226da).
[0427] Halopropane by-products having a lower degree of
fluorination than HCFC-226da that may be formed in step (a) include
CF.sub.3CHClCClF.sub.2 (HCFC-225da). Other halopropane by-products
which may be formed include CFC-216aa
(CF.sub.3CCl.sub.2CF.sub.3).
[0428] Halopropene by-products having a lower degree of
fluorination than CFC-1215xc that may be formed in step (a) include
E- and Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb, C.sub.3Cl.sub.2F.sub.4
isomers) and CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa).
[0429] Prior to step (b), CFC-1215xc and HCFC-226da (and optionally
HF) from the effluent from the reaction zone in step (a), are
typically separated from lower boiling components of the effluent
(which typically comprise HCl) and the underfluorinated components
of the effluent (which typically comprise HCFC-225da,
C.sub.3Cl.sub.2F.sub.4 isomers, and CFC-1213xa).
[0430] In one embodiment of the invention, the reactor effluent
from step (a) may be delivered to a first distillation column in
which HCl and any HCl azeotropes are removed from the top of column
while the higher boiling components are removed at the bottom of
the column. The products recovered at the bottom of the first
distillation column are then delivered to a second distillation
column in which CF.sub.3CHClCF.sub.3, CF.sub.3CCl.dbd.CF.sub.2, and
HF, are separated at the top of the column, and any remaining HF
and underfluorinated components are removed from the bottom of the
column.
[0431] The mixture of CF.sub.3CHClCF.sub.3,
CF.sub.3CCl.dbd.CF.sub.2, and HF recovered from the top of the
second distillation column may be delivered to step (b) or may
optionally be delivered to a decanter maintained at a suitable
temperature to cause separation of an organic-rich liquid phase and
an HF-rich liquid phase. The HF-rich phase may be distilled to
recover HF that is then recycled to step (a). The organic-rich
phase may then be delivered to step (b) or may be processed to
produce HCFC-226da and CFC-1215xc individually or as mixture.
[0432] In another embodiment of the invention said underfluorinated
components such as HCFC-225da, C.sub.3Cl.sub.2F.sub.4 isomers, and
CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa) may be returned to step
(a).
[0433] In connection with developing processes for the separation
of CFC-1215xc, it is noted that CFC-1215xc can be present as an
azeotrope with HF.
[0434] Further information on azeotropic compositions of CFC-1215xc
and HF is disclosed in U.S. Patent Application 60/927,818 [FL-1339
US PRV], filed May 4, 2007 and hereby incorporated herein by
reference.
[0435] In step (b) of the process of this invention, the
CF.sub.3CHClCF.sub.3 and/or CF.sub.3CCl.dbd.CF.sub.2 produced in
step (a) are reacted with hydrogen (H.sub.2), optionally in the
presence of HF.
[0436] In one embodiment of step (b), a mixture comprising
CFC-1215xc and/or HCFC-226da produced in step (a), and optionally
HF, is delivered in the vapor phase, along with hydrogen (H.sub.2),
to a reactor containing a hydrogenation catalyst.
[0437] Hydrogenation catalysts suitable for use in this embodiment
include catalysts comprising at least one metal selected from the
group consisting of iron, ruthenium, rhodium, iridium, palladium,
and platinum. Said catalytic metal component is typically supported
on a carrier such as carbon or graphite or a metal oxide,
fluorinated metal oxide, or metal fluoride where the carrier metal
is selected from the group consisting of magnesium, aluminum,
titanium, vanadium, chromium, iron, and lanthanum.
[0438] Of note are carbon supported catalysts in which the carbon
support has been washed with acid and has an ash content below
about 0.1% by weight. Hydrogenation catalysts supported on low ash
carbon that are suitable for carrying out step (b) of the process
of this invention are described in U.S. Pat. No. 5,136,113, the
teachings of which are incorporated herein by reference. Also of
note are catalysts comprising at least one metal selected from the
group consisting of palladium, platinum, and rhodium supported on
alumina (Al.sub.2O.sub.3), fluorinated alumina, or aluminum
fluoride (AlF.sub.3).
[0439] The supported metal catalysts may be prepared by
conventional methods known in the art such as by impregnation of
the carrier with a soluble salt of the catalytic metal (e.g.,
palladium chloride or rhodium nitrate) as described by Satterfield
on page 95 of Heterogenous Catalysis in Industrial Practice,
2.sup.nd edition (McGraw-Hill, New York, 1991). The concentration
of the catalytic metal(s) on the support is typically in the range
of about 0.1% by weight of the catalyst to about 5% by weight.
[0440] The relative amount of hydrogen contacted with CFC-1215xc
and HCFC-226da in the presence of the hydrogenation catalyst is
typically from about the stoichiometric ratio of hydrogen to
CF.sub.3CHClCF.sub.3/CF.sub.3CCl.dbd.CF.sub.2 mixture to about 10
moles of H.sub.2 per mole of
CF.sub.3CHClCF.sub.3/CF.sub.3CCl.dbd.CF.sub.2 mixture. The
stoichiometric ratio of hydrogen to the
CF.sub.3CHClCF.sub.3/CF.sub.3CCl.dbd.CF.sub.2 mixture depends on
the relative amounts of the two components in the mixture. The
stoichiometric amounts of H.sub.2 required to convert HCFC-226da
and CFC-1215xc to CF.sub.3CH.sub.2CF.sub.3 and
CF.sub.3CH.sub.2CHF.sub.2, are one and two moles, respectively.
[0441] Suitable temperatures for the catalytic hydrogenation are
typically from about 100.degree. C. to about 350.degree. C.,
preferably from about 125.degree. C. to about 300.degree. C.
Temperatures above about 350.degree. C. tend to result in
defluorination side reactions; temperatures below about 125.degree.
C. will result in incomplete substitution of Cl for H in the
starting materials. The reactions are typically conducted at
atmospheric pressure or superatmospheric pressure.
[0442] The effluent from the step (b) reaction zone(s) typically
includes HCl, CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa),
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa), and small amounts of lower
boiling by-products (typically including propane,
CF.sub.3CH.dbd.CF.sub.2 (HFC-1225zc), E- and Z-CF.sub.3CH.dbd.CHF
(HFC-1234ze), and/or CF.sub.3CH.sub.2CH.sub.3 (HFC-263fb)) and
higher boiling by-products and intermediates (typically including
CF.sub.3CHFCH.sub.3 (HFC-254eb) and/or CF.sub.3CHClCHF.sub.2
(HCFC-235da)) as well as any unconverted starting materials and any
HF carried over from step (a).
[0443] In step (c), the desired products are recovered. Products
from step (b) may be delivered to a separation unit to recover at
least one of CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CH.sub.2CHF.sub.2
individually, as a mixture, or as their HF azeotropes.
[0444] Partially chlorinated components such as HCFC-235da may be
recovered and recycled back to step (b).
[0445] In one embodiment CF.sub.3CH.sub.2CF.sub.3 and/or
CF.sub.3CH.sub.2CHF.sub.2 recovered from step (c) may be
dehydrofluorinated to produce CF.sub.3CH.dbd.CF.sub.2 and/or E- and
Z-CF.sub.3CH.dbd.CHF respectively, as disclosed in U.S. Patent
Application 60/927,842 [FL-1363 US PRV] filed May 4, 2007 and
hereby incorporated herein by reference.
[0446] Embodiments of this invention include, but are not limited
to:
[0447] Embodiment F1. A process for making at least one compound
selected from CF.sub.3CH.sub.2CHF.sub.2 and
CF.sub.3CH.sub.2CF.sub.3, comprising (a) reacting HF, and at least
one halopropene of the formula CX.sub.3CCl.dbd.CClX, wherein each X
is independently selected from the group consisting of F and Cl, to
produce a product comprising at least one compound selected from
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3, wherein said
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 are produced in
the presence of a catalyst composition comprising chromium, oxygen,
and at least two modifier metals selected from the group consisting
of gold, silver and palladium as essential constituent elements,
wherein the total amount of modifier metals in said catalyst
composition is from about 0.05 atom % to about 10 atom % based on
the total amount of chromium and modifier metals in the catalyst
composition; (b) reacting at least one compound selected from
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 produced in (a)
with H.sub.2, optionally in the presence of HF, to produce a
product comprising at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3; and (c)
recovering at least one compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 from the
product produced in (b).
[0448] Embodiment F2. The process of Embodiment F1 wherein the
halopropene reactant is contacted with HF in a pre-reactor.
[0449] Embodiment F3. The process of Embodiment F1 wherein the
reaction of (b) is conducted in a reaction zone at a temperature of
from about 100.degree. C. to about 350.degree. C. containing a
hydrogenation catalyst.
[0450] Embodiment F4. The process of Embodiment F1 wherein the
amount of modifier metals relative to the total amount of chromium
and modifier metals in the catalyst composition is from about 0.5
atom % to about 5 atom %.
[0451] Embodiment F5. The process of Embodiment F1 wherein the
catalyst composition further comprises fluorine as an essential
constituent element.
[0452] Embodiment F6. The process of Embodiment F1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and metallic silver.
[0453] Embodiment F7. The process of Embodiment F1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and palladium.
[0454] Embodiment F8. The process of Embodiment F1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic
silver and palladium.
[0455] Embodiment F9. The process of Embodiment F1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold,
metallic silver and palladium.
[0456] Embodiment F10. The process of Embodiment F1 wherein the
catalyst composition comprises silver and gold and the mole ratio
of silver to gold is from about 10:1 to about 1:10.
[0457] Embodiment F11. The process of Embodiment F1 wherein the
catalyst composition comprises silver and palladium and the mole
ratio of silver to palladium is from about 10:1 to about 1:10.
[0458] Embodiment F12. The process of Embodiment F1 wherein the
catalyst composition comprises palladium and gold and the mole
ratio of palladium to gold is from about 10:1 to about 1:10
Examples
[0459] Reference is made to Examples A1-A5 in Invention Category A
above for the chlorofluorination of CFC-1213xa.
[0460] Examination of the data in Table A1 above shows that the
fluorine content of the starting material CFC-1213xa is increased
to produce CFC-1215xc and HCFC-226da that contain a higher fluorine
content than the starting material by using the catalysts of this
invention.
G.
[0461] Invention Category G of this application provides a process
for the manufacture of CF.sub.3CH.dbd.CHF (HFC-1234ze),
CF.sub.3CH.dbd.CF.sub.2 (HFC-1225zc), or both CF.sub.3CH.dbd.CHF
and CF.sub.3CH.dbd.CF.sub.2. The HFC-1234ze and HFC-1225zc may be
recovered as individual products and/or as one or more mixtures of
the two products. HFC-1234ze may exist as one of two
configurational isomers, E or Z. HFC-1234ze as used herein refers
to the isomers, E-HFC-1234ze or Z-HFC-1234ze, as well as any
combinations or mixtures of such isomers.
[0462] In step (a) of the process of this invention, one or more
halopropene compounds of the formula CX.sub.3CCl.dbd.CClX, wherein
each X is independently selected from the group consisting of F and
Cl, are reacted with hydrogen fluoride (HF) to produce a product
mixture comprising at least one of CF.sub.3CCl.dbd.CF.sub.2
(CFC-1215xc) and CF.sub.3CHClCF.sub.3 (HCFC-226da). Accordingly,
this invention provides a process for the preparation of at least
one of CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 from
readily available starting materials.
[0463] Suitable starting materials for the process of this
invention include E- and Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb),
CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa), CClF.sub.2CCl.dbd.CCl.sub.2
(CFC-1212xa), CCl.sub.2FCCl.dbd.CCl.sub.2 (CFC-1211xa), and
CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene, HCP), or mixtures
thereof.
[0464] Due to their availability, CF.sub.3CCl.dbd.CCl.sub.2
(CFC-1213xa) and CCl.sub.3CCl.dbd.CCl.sub.2 (hexachloropropene,
HCP) are the preferred starting materials for the process of the
invention.
[0465] Preferably, the reaction of HF with CX.sub.3CCl.dbd.CClX is
carried out in the vapor phase in a heated tubular reactor. A
number of reactor configurations are possible, including vertical
and horizontal orientation of the reactor and different modes of
contacting the halopropene starting material(s) with HF. Preferably
the HF is substantially anhydrous.
[0466] In one embodiment of step (a), the halopropene starting
material(s) and HF may be fed to the reactor containing the
fluorination catalyst. The halopropene starting material(s) may be
initially vaporized and fed to the reactor as gas(es).
[0467] In another embodiment of step (a), the halopropene starting
material(s) may be contacted with HF in a pre-reactor (i.e. prior
to contacting the fluorination catalyst). The pre-reactor may be
empty (i.e., unpacked), but is preferably filled with a suitable
packing such as Monel.TM. or Hastelloy.TM. nickel alloy turnings or
wool, or other material inert to HCl and HF, for efficient mixing
of CX.sub.3CCl.dbd.CClX and HF.
[0468] If the halopropene starting material(s) are fed to the
pre-reactor as liquid(s), it is preferable for the pre-reactor to
be oriented vertically with CX.sub.3CCl.dbd.CClX entering the top
of the reactor and pre-heated HF vapor introduced at the bottom of
the reactor.
[0469] Suitable temperatures for the pre-reactor are within the
range of from about 80.degree. C. to about 250.degree. C.,
preferably from about 100.degree. C. to about 200.degree. C. Under
these conditions, for example, hexachloropropene is converted to a
mixture containing predominantly CFC-1213xa. The feed rate of the
starting material is determined by the length and diameter of the
reactor, reactor temperature, and the degree of fluorination
desired in the pre-reactor. Slower feed rates at a given
temperature will increase contact time and tend to increase the
amount of conversion of the starting material and increase the
degree of fluorination of the products.
[0470] The term "degree of fluorination" means the extent to which
fluorine atoms replace chlorine substituents in the
CX.sub.3CCl.dbd.CClX starting materials. For example,
CF.sub.3CCl.dbd.CClF represents a higher degree of fluorination
than CClF.sub.2CCl.dbd.CCl.sub.2 and CF.sub.3CCl.sub.2CF.sub.3
represents a higher degree of fluorination than
CClF.sub.2CCl.sub.2CF.sub.3.
[0471] The molar ratio of HF fed to the pre-reactor, or otherwise
to the reaction zone of step (a), to halopropene starting material
fed in step (a) is typically from about stoichiometric to about
50:1. The stoichiometric ratio depends on the average degree of
fluorination of the halopropene starting material(s) and is
typically based on formation of C.sub.3ClF.sub.5. For example, if
the halopropene is HCP, the stoichiometric ratio of HF to HCP is
5:1; if the halopropene is CFC-1213xa, the stoichiometric ratio of
HF to CFC-1213xa is 2:1. Preferably, the molar ratio of HF to
halopropene starting material is from about twice the
stoichiometric ratio (based on formation of C.sub.3ClF.sub.5) to
about 30:1. Higher ratios of HF to halopropene are not particularly
beneficial. Lower ratios result in reduced yields of CFC-1215xc and
HCFC-226da.
[0472] In a preferred embodiment of step (a) the halopropene
starting materials are vaporized, preferably in the presence of HF,
contacted with HF in a pre-reactor, and then contacted with the
fluorination catalyst. If the preferred amount of HF is fed in the
pre-reactor, additional HF is not required in the reaction zone(s)
of step (a).
[0473] Suitable temperatures in the reaction zone(s) of step (a)
for catalytic fluorination of halopropene starting materials and/or
their products formed in the pre-reactor are within the range of
about 200.degree. C. to about 400.degree. C., preferably from about
240.degree. C. to about 350.degree. C., depending on the desired
conversion of the starting material and the activity of the
catalyst. Higher temperatures typically contribute to reduced
catalyst life. Temperatures below about 240.degree. C. may result
in substantial amounts of products having a degree of fluorination
less than five (i.e., underfluorinates). By adjusting process
conditions such as temperature, contact time, and HF ratios,
greater or lesser amounts of CFC-1215xc relative to HCFC-226da can
be formed.
[0474] Suitable reactor pressures for vapor phase embodiments of
this invention may be in the range of from about 1 to about 30
atmospheres. Reactor pressures of about 5 atmospheres to about 20
atmospheres may be advantageously employed to facilitate separation
of HCl from other reaction products in step (b) of the process.
[0475] The fluorination catalysts used in step (a) of this
invention comprise chromium, oxygen and modifier metals (e.g.,
modifier metal-containing chromium oxide) and contain from about
0.05 atom % to about 10 atom % modifier metals based on the total
amount of modifier metals and chromium in the catalyst composition.
Of note are compositions comprising silver and gold wherein the
mole ratio of silver to gold is from about 10:1 to about 1:10. Also
of note are compositions comprising silver and palladium wherein
the mole ratio of silver to palladium is from about 10:1 to about
1:10. Also of note are compositions comprising palladium and gold
wherein the mole ratio of palladium to gold is from about 10:1 to
about 1:10.
[0476] In one embodiment of this invention, the catalyst
composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and metallic silver (i.e., silver in the zero
oxidation state). In another embodiment of this invention, the
catalyst composition comprises alpha-chromium oxide (i.e.,
.quadrature.-Cr.sub.2O.sub.3) and metallic gold (i.e., gold in the
zero oxidation state) and palladium. In another embodiment of this
invention, the catalyst composition comprises alpha-chromium oxide
(i.e., .quadrature.-Cr.sub.2O.sub.3) and metallic silver (i.e.,
silver in the zero oxidation state) and palladium. In another
embodiment of this invention, the catalyst composition comprises
alpha-chromium oxide (i.e., .quadrature.-Cr.sub.2O.sub.3), metallic
gold (i.e., gold in the zero oxidation state), metallic silver
(i.e., silver in the zero oxidation state), and palladium. Of note
are embodiments wherein at least 50 weight % of the chromium
component is present as alpha-chromium oxide. Also of note are
embodiments wherein the gold component consists essentially of
metallic gold having an average particle size of from about 1
nanometer to about 500 nanometers. In certain embodiments of this
invention, particles of metallic gold and at least one of palladium
and metallic silver are dispersed in a matrix comprising chromium
oxide. In certain embodiments of this invention, particles of
metallic silver and palladium are dispersed in a matrix comprising
chromium oxide.
[0477] In certain embodiments of this invention, particles of
metallic gold and at least one of palladium and metallic silver are
supported on a chromium oxide support. In some embodiments,
particles of metallic silver and palladium are supported on a
chromium oxide support.
[0478] The catalyst compositions of this invention may further
comprise fluorine as an essential constituent element.
[0479] The amount of modifier metals relative to the total amount
of chromium and modifier metals in the catalyst compositions used
for the fluorination reaction is preferably from about 0.5 atom %
to about 5 atom %.
[0480] Further information on catalyst compositions comprising
chromium, oxygen, and at least two modifier metals selected from
the group consisting of gold, silver, and palladium as essential
constituent elements useful for this invention (including
embodiments further comprising fluorine) is provided in Invention
Category A above and in U.S. Patent Applications 60/903,218 [FL
1356 US PRV] filed Feb. 23, 2007, and 60/927,846 [FL 1356 US PRV1]
filed May 4, 2007, hereby incorporated herein by reference in their
entirety.
[0481] The modifier metal-containing chromium oxide catalysts used
in the present invention can be formed into various shapes such as
pellets, granules, and extrudates for use in packing reactors. They
can also be used in powder forms.
[0482] The catalyst compositions used in step (a) of this invention
may further comprise one or more additives in the form of metal
compounds. Such additives may alter the selectivity and/or activity
of the modifier metal-containing chromium oxide catalyst
compositions or the fluorinated modifier metal-containing chromium
oxide catalyst compositions. Suitable additives can be selected
from the group consisting of the fluorides, oxides, and oxyfluoride
compounds of Mg, Ca, Sc, Y, La, Ti, Zr, W, Mn, Re, Fe, Ru, Co, Rh,
Ir, Ni, Pt, Ce, and Zn.
[0483] The total content of the additive(s) in the catalyst
compositions used in step (a) of the present invention may be from
about 0.05 weight % to about 10 weight % based on the total metal
content of the catalyst compositions. The additives may be
incorporated into the catalyst compositions by standard procedures
such as by impregnation or during co-precipitation of the modifier
metal and chromium salts.
[0484] The catalyst compositions used in step (a) of the present
invention can be treated with a fluorinating agent to form catalyst
compositions comprising chromium, oxygen, modifier metals and
fluorine as essential elements. Typically, prior to use as
catalysts, the catalyst compositions are pre-treated with a
fluorinating agent. Typically this fluorinating agent is HF though
other materials may be used such as sulfur tetrafluoride, carbonyl
fluoride, and fluorinated hydrocarbon compounds such as
trichlorofluoromethane, dichlorodifluoromethane,
chlorodifluoromethane, trifluoromethane, and
1,1,2-trichlorotrifluoroethane. This pretreatment can be
accomplished, for example, by placing the catalyst composition in a
suitable container which can also be the reactor to be used to
perform the process in the present invention, and thereafter,
passing HF over the calcined catalyst composition so as to
partially saturate the catalyst composition with HF. This can be
conveniently carried out by passing HF over the catalyst
composition for a period of time, for example, about 0.1 to about
10 hours at a temperature of, for example, about 200.degree. C. to
about 450.degree. C. Nevertheless, this pre-treatment is not
essential.
[0485] Compounds that are produced in the fluorination process step
(a) include the CF.sub.3CCl.dbd.CF.sub.2 (CFC-1215xc) and
CF.sub.3CHClCF.sub.3 (HCFC-226da).
[0486] Halopropane by-products having a lower degree of
fluorination than HCFC-226da that may be formed in step (a) include
CF.sub.3CHClCClF.sub.2 (HCFC-225da). Other halopropane by-products
which may be formed include CFC-216aa
(CF.sub.3CCl.sub.2CF.sub.3).
[0487] Halopropene by-products having a lower degree of
fluorination than CFC-1215xc that may be formed in step (a) include
E- and Z-CF.sub.3CCl.dbd.CClF (CFC-1214xb, C.sub.3Cl.sub.2F.sub.4
isomers) and CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa).
[0488] Prior to step (b), CFC-1215xc and HCFC-226da (and optionally
HF) from the effluent from the reaction zone in step (a), are
typically separated from lower boiling components of the effluent
(which typically comprise HCl) and the underfluorinated components
of the effluent (which typically comprise HCFC-225da,
C.sub.3Cl.sub.2F.sub.4 isomers, and CFC-1213xa).
[0489] In one embodiment of the invention, the reactor effluent
from step (a) may be delivered to a first distillation column in
which HCl and any HCl azeotropes are removed from the top of column
while the higher boiling components are removed at the bottom of
the column. The products recovered at the bottom of the first
distillation column are then delivered to a second distillation
column in which CF.sub.3CHClCF.sub.3, CF.sub.3CCl.dbd.CF.sub.2, and
HF, are separated at the top of the column, and any remaining HF
and underfluorinated components are removed from the bottom of the
column.
[0490] The mixture of CF.sub.3CHClCF.sub.3,
CF.sub.3CCl.dbd.CF.sub.2, and HF recovered from the top of the
second distillation column may be delivered to step (b) or may
optionally be delivered to a decanter maintained at a suitable
temperature to cause separation of an organic-rich liquid phase and
an HF-rich liquid phase. The HF-rich phase may be distilled to
recover HF that is then recycled to step (a). The organic-rich
phase may then be delivered to step (b) or may be processed to
produce HCFC-226da and CFC-1215xc individually or as a mixture.
[0491] In another embodiment of the invention said underfluorinated
components such as HCFC-225da, C.sub.3Cl.sub.2F.sub.4 isomers, and
CF.sub.3CCl.dbd.CCl.sub.2 (CFC-1213xa) may be returned to step
(a).
[0492] In step (b) of the process of this invention, the
CF.sub.3CHClCF.sub.3 and/or CF.sub.3CCl.dbd.CF.sub.2 produced in
step (a) are reacted with hydrogen (H.sub.2), optionally in the
presence of HF.
[0493] In one embodiment of step (b), a mixture comprising
CFC-1215xc and/or HCFC-226da produced in step (a), and optionally
HF, is delivered in the vapor phase, along with hydrogen (H.sub.2),
to a reactor containing a hydrogenation catalyst.
[0494] Hydrogenation catalysts suitable for use in this embodiment
include catalysts comprising at least one metal selected from the
group consisting of iron, ruthenium, rhodium, iridium, palladium,
and platinum. Said catalytic metal component is typically supported
on a carrier such as carbon or graphite or a metal oxide,
fluorinated metal oxide, or metal fluoride where the carrier metal
is selected from the group consisting of magnesium, aluminum,
titanium, vanadium, chromium, iron, and lanthanum.
[0495] Of note are carbon supported catalysts in which the carbon
support has been washed with acid and has an ash content below
about 0.1% by weight. Hydrogenation catalysts supported on low ash
carbon that are suitable for carrying out step (b) of the process
of this invention are described in U.S. Pat. No. 5,136,113, the
teachings of which are incorporated herein by reference. Also of
note are catalysts comprising at least one metal selected from the
group consisting of palladium, platinum, and rhodium supported on
alumina (Al.sub.2O.sub.3), fluorinated alumina, or aluminum
fluoride (AlF.sub.3).
[0496] The supported metal catalysts may be prepared by
conventional methods known in the art such as by impregnation of
the carrier with a soluble salt of the catalytic metal (e.g.,
palladium chloride or rhodium nitrate) as described by Satterfield
on page 95 of Heterogenous Catalysis in Industrial Practice,
2.sup.nd edition (McGraw-Hill, New York, 1991). The concentration
of the catalytic metal(s) on the support is typically in the range
of about 0.1% by weight of the catalyst to about 5% by weight.
[0497] The relative amount of hydrogen contacted with CFC-1215xc
and HCFC-226da in the presence of the hydrogenation catalyst is
typically from about the stoichiometric ratio of hydrogen to
CF.sub.3CHClCF.sub.3/CF.sub.3CCl.dbd.CF.sub.2 mixture to about 10
moles of H.sub.2 per mole of
CF.sub.3CHClCF.sub.3/CF.sub.3CCl.dbd.CF.sub.2 mixture. The
stoichiometric ratio of hydrogen to the
CF.sub.3CHClCF.sub.3/CF.sub.3CCl.dbd.CF.sub.2 mixture depends on
the relative amounts of the two components in the mixture. The
stoichiometric amounts of H.sub.2 required to convert HCFC-226da
and CFC-1215xc to CF.sub.3CH.sub.2CF.sub.3 and
CF.sub.3CH.sub.2CHF.sub.2, are one and two moles, respectively.
[0498] Suitable temperatures for the catalytic hydrogenation are
typically from about 100.degree. C. to about 350.degree. C.,
preferably from about 125.degree. C. to about 300.degree. C.
Temperatures above about 350.degree. C. tend to result in
defluorination side reactions; temperatures below about 125.degree.
C. will result in incomplete substitution of Cl for H in the
starting materials. The reactions are typically conducted at
atmospheric pressure or superatmospheric pressure.
[0499] The effluent from the step (b) reaction zone(s) typically
includes HCl, CF.sub.3CH.sub.2CF.sub.3 (HFC-236fa),
CF.sub.3CH.sub.2CHF.sub.2 (HFC-245fa), and small amounts of lower
boiling by-products (typically including propane,
CF.sub.3CH.dbd.CF.sub.2 (HFC-1225zc), E- and Z-CF.sub.3CH.dbd.CHF
(HFC-1234ze), and/or CF.sub.3CH.sub.2CH.sub.3 (HFC-263fb)) and
higher boiling by-products and intermediates (typically including
CF.sub.3CHFCH.sub.3 (HFC-254eb) and/or CF.sub.3CHClCHF.sub.2
(HCFC-235da)) as well as any unconverted starting materials and any
HF carried over from step (a).
[0500] In one embodiment of step (b), at least one of
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 produced in
step (b) are recovered individually, as a mixture, or as their HF
azeotropes as disclosed in U.S. Patent Application 60/927,843
[FL-1362 US PRV] filed May 4, 2007 and hereby incorporated herein
by reference.
[0501] In step (c) of the process, CF.sub.3CH.sub.2CHF.sub.2 and/or
CF.sub.3CH.sub.2CF.sub.3 produced in step (b) are
dehydrofluorinated.
[0502] In one embodiment of step (c), a mixture comprising
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3, and
optionally an inert gas, is delivered in the vapor phase to a
reaction zone containing a dehydrofluorination catalyst as
described in U.S. Pat. No. 6,369,284; the teachings of this
disclosure are incorporated herein by reference.
[0503] Dehydrofluorination catalysts suitable for use in this
embodiment include (1) at least one compound selected from the
oxides, fluorides and oxyfluorides of magnesium, zinc and mixtures
of magnesium and zinc, (2) lanthanum oxide, (3) fluorided lanthanum
oxide, (4) activated carbon, and (5) three-dimensional matrix
carbonaceous materials.
[0504] The catalytic dehydrofluorination of
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 is suitably
conducted at a temperature in the range of from about 200.degree.
C. to about 500.degree. C., and preferably from about 350.degree.
C. to about 450.degree. C. The contact time is typically from about
1 to about 450 seconds, preferably from about 10 to about 120
seconds.
[0505] The reaction pressure can be subatmospheric, atmospheric or
superatmospheric. Generally, near atmospheric pressures are
preferred. However, the dehydrofluorination of
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 can be
beneficially run under reduced pressure (i.e., pressures less than
one atmosphere).
[0506] The catalytic dehydrofluorination can optionally be carried
out in the presence of an inert gas such as nitrogen, helium or
argon. The addition of an inert gas can be used to increase the
extent of dehydrofluorination. Of note are processes where the mole
ratio of inert gas to CF.sub.3CH.sub.2CHF.sub.2 and/or
CF.sub.3CH.sub.2CF.sub.3 is from about 5:1 to 1:1. Nitrogen is the
preferred inert gas.
[0507] The products from the step (c) reaction zone typically
include HF, E- and Z-forms of CF.sub.3CH.dbd.CHF (HFC-1234ze),
CF.sub.3CH.dbd.CF.sub.2 (HFC-1225zc), CF.sub.3CH.sub.2CHF.sub.2,
CF.sub.3CH.sub.2CF.sub.3, and small amounts of other products.
Unconverted CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3
are recycled back to the dehydrofluorination reactor to produce
additional quantities of CF.sub.3CF.dbd.CHF and
CF.sub.3CH.dbd.CF.sub.2.
[0508] In another embodiment of step (c), the
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 are
subjected to dehydrofluorination at an elevated temperature in the
absence of a catalyst following procedures similar to those
disclosed in U.S. Patent Application Publication No. 2006/0094911
which is incorporated herein by reference. The reactor can be
fabricated from nickel, iron, titanium, or their alloys, as
described in U.S. Pat. No. 6,540,933; the teachings of this
disclosure are incorporated herein by reference.
[0509] The temperature of the reaction in this embodiment can be
between about 350.degree. C. and about 900.degree. C., and is
preferably at least about 450.degree. C.
[0510] In yet another embodiment of step (c), the
CF.sub.3CH.sub.2CF.sub.3 and CF.sub.3CH.sub.2CHF.sub.2 are
dehydrofluorinated by reaction with caustic (e.g. KOH) using
procedures known to the art.
[0511] In step (d) of the process, at least one of
CF.sub.3CH.dbd.CHF and CF.sub.3CH.dbd.CF.sub.2 produced in step (c)
are recovered individually and/or as one or more mixtures of
CF.sub.3CH.dbd.CHF and CF.sub.3CH.dbd.CF.sub.2 by well known
procedures such as distillation.
[0512] Embodiments of this invention include, but are not limited
to:
[0513] Embodiment G1. A process for the manufacture of at least one
compound selected from the group consisting of
1,3,3,3-tetrafluoropropene and 1,1,3,3,3-pentafluoropropene,
comprising (a) reacting HF, and at least one halopropene of the
formula CX.sub.3CCl.dbd.CClX, wherein each X is independently
selected from the group consisting of F and Cl, to produce a
product comprising at least compound selected from
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3, wherein said
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 are produced in
the presence of a catalyst composition comprising chromium, oxygen,
and at least two modifier metals selected from the group consisting
of gold, silver, and palladium as essential constituent elements,
wherein the total amount of modifier metals in said catalyst
composition is from about 0.05 atom % to about 10 atom % based on
the total amount of chromium and modifier metals in the catalyst
composition; (b) reacting at least compound selected from
CF.sub.3CCl.dbd.CF.sub.2 and CF.sub.3CHClCF.sub.3 produced in (a)
with H.sub.2, optionally in the presence of HF, to produce a
product comprising at least compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3; and (c)
dehydrofluorinating at least compound selected from
CF.sub.3CH.sub.2CHF.sub.2 and CF.sub.3CH.sub.2CF.sub.3 produced in
(b) to produce a product comprising at least compound selected from
CF.sub.3CH.dbd.CHF and CF.sub.3CH.dbd.CF.sub.2; and (d) recovering
at least one compound selected from the group consisting of
CF.sub.3CH.dbd.CHF and CF.sub.3CH.dbd.CF.sub.2 from the product
produced in (c).
[0514] Embodiment G2. The process of Embodiment G1 wherein the
halopropene reactant is contacted with HF in a pre-reactor.
[0515] Embodiment G3. The process of Embodiment G1 wherein the
reaction of (b) is conducted in a reaction zone at a temperature of
from about 100.degree. C. to about 350.degree. C. containing a
hydrogenation catalyst.
[0516] Embodiment G4. The process of Embodiment G1 wherein the
reaction of (c) is conducted in the absence of a catalyst at a
temperature of from about 350.degree. C. to about 900.degree.
C.
[0517] Embodiment G5. The process of Embodiment G1 wherein the
reaction of (c) is conducted in a reaction zone containing a
dehydrofluorination catalyst at a temperature of from about
200.degree. C. to about 500.degree. C.
[0518] Embodiment G6. The process of Embodiment G1 wherein the
amount of modifier metals relative to the total amount of chromium
and modifier metals in the catalyst composition is from about 0.5
atom % to about 5 atom %.
[0519] Embodiment G7. The process of Embodiment G1 wherein the
catalyst composition further comprises fluorine as an essential
constituent element.
[0520] Embodiment G8. The process of Embodiment G1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and metallic silver.
[0521] Embodiment G9. The process of Embodiment G1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold
and palladium.
[0522] Embodiment G10. The process of Embodiment G1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic
silver and palladium.
[0523] Embodiment G11. The process of Embodiment G1 wherein the
catalyst composition comprises alpha-chromium oxide, metallic gold,
metallic silver and palladium.
[0524] Embodiment G12. The process of Embodiment G1 wherein the
catalyst composition comprises silver and gold and the mole ratio
of silver to gold is from about 10:1 to about 1:10.
[0525] Embodiment G13. The process of Embodiment G1 wherein the
catalyst composition comprises silver and palladium and the mole
ratio of silver to palladium is from about 10:1 to about 1:10.
[0526] Embodiment G14. The process of Embodiment G1 wherein the
catalyst composition comprises palladium and gold and the mole
ratio of palladium to gold is from about 10:1 to about 1:10
Examples
[0527] Reference is made to Examples A1-A5 in Invention Category A
above for the chlorofluorination of CFC-1213xa.
[0528] Examination of the data in Table A1 above shows that the
fluorine content of the starting CFC-1213xa is increased to produce
CFC-1215xc and HCFC-226da that contain a higher fluorine content
than the starting material by using the catalysts of this
invention. The CFC-1215xc and HCFC-226da produced above may be
hydrogenated to produce HFC-245fa and HFC-236fa, respectively, in a
manner analogous to the teachings of U.S. Pat. No. 5,136,113. For
example, the HFC-245fa and HFC-236fa may be dehydrofluorinated to
HFC-1234ze and HFC-1225zc, respectively, in accordance with the
teachings described in U.S. Pat. No. 6,369,284. The HFC-1234ze and
HFC-1225zc may be recovered individually or as mixtures of
HFC-1234ze and HFC-1225zc by procedures known to the art.
[0529] The reactor, distillation columns, and their associated feed
lines, effluent lines, and associated units used in applying the
processes described in Invention Categories A through G should be
constructed of materials resistant to hydrogen fluoride and
hydrogen chloride. Typical materials of construction, well-known to
the fluorination art, include stainless steels, in particular of
the austenitic type, the well-known high nickel alloys, such as
Monel.TM. nickel-gold alloys, Hastelloy.TM. nickel-based alloys
and, Inconel.TM. nickel-chromium alloys, and gold-clad steel.
[0530] Without further elaboration, it is believed that one skilled
in the art can, using the descriptions herein (including the
description in Invention Categories A through G above), utilize the
present invention to its fullest extent. The specific embodiments
are, therefore, to be construed as merely illustrative, and do not
constrain the remainder of the disclosure in any way
whatsoever.
* * * * *